How much can the human body withstand. Problems in physics with elements of astronomy What kind of electric shock can we withstand

According to the degree of impact of climatic and geographical factors on a person, the existing classification subdivides (conditionally) mountain levels into:

Lowlands - up to 1000 m. Here a person does not experience (compared to the area located at sea level) the negative effect of a lack of oxygen even during hard work;

Middle Mountains - ranging from 1000 to 3000 m. Here, under conditions of rest and moderate activity, no significant changes occur in the body of a healthy person, since the body easily compensates for the lack of oxygen;

Highlands - over 3000 m. These heights are characterized by the fact that even at rest in the body of a healthy person, a complex of changes caused by oxygen deficiency is detected.

If at medium altitudes the human body is affected by the whole complex of climatic and geographical factors, then at high mountains, the lack of oxygen in the tissues of the body, the so-called hypoxia, is of decisive importance.

Highlands, in turn, can also be conditionally divided (Fig. 1) into the following zones (according to E. Gippenreiter):

a) Full acclimatization zone - up to 5200-5300 m. In this zone, due to the mobilization of all adaptive reactions, the body successfully copes with oxygen deficiency and the manifestation of other negative factors of altitude. Therefore, here it is still possible to have long-term posts, stations, etc., that is, to live and work permanently.

b) Zone of incomplete acclimatization - up to 6000 m. Here, despite the commissioning of all compensatory-adaptive reactions, the human body can no longer fully counteract the influence of height. With a long (for several months) stay in this zone, fatigue develops, a person weakens, loses weight, atrophy of muscle tissues is observed, activity decreases sharply, the so-called high-altitude deterioration develops - a progressive deterioration in the general condition of a person with prolonged stay at high altitudes.

c) Adaptation zone - up to 7000 m. The adaptation of the body to altitude here is of a short, temporary nature. Even with a relatively short stay (on the order of two or three weeks) at such altitudes, adaptation reactions become depleted. In this regard, the body shows clear signs of hypoxia.

d) Zone of partial adaptation - up to 8000 m. When staying in this zone for 6-7 days, the body cannot provide the necessary amount of oxygen even to the most important organs and systems. Therefore, their activities are partially disrupted. Thus, the reduced efficiency of systems and organs responsible for replenishing energy costs does not ensure the restoration of strength, and human activity is largely due to reserves. At such altitudes, severe dehydration of the body occurs, which also worsens its general condition.

e) Limit (lethal) zone - over 8000 m. Gradually losing resistance to the action of heights, a person can stay at these heights due to internal reserves only for an extremely limited time, about 2 - 3 days.

The above values ​​of the altitudinal boundaries of the zones are, of course, average values. Individual tolerance, as well as a number of factors outlined below, can change the indicated values ​​\u200b\u200bfor each climber by 500 - 1000 m.

Adaptation of the body to altitude depends on age, sex, physical and mental state, degree of fitness, degree and duration of oxygen starvation, intensity of muscle effort, and experience at altitude. An important role is played by the individual resistance of the organism to oxygen starvation. Previous diseases, malnutrition, insufficient rest, lack of acclimatization significantly reduce the body's resistance to mountain sickness - a special condition of the body that occurs when inhaling rarefied air. Of great importance is the speed of climb. These conditions explain the fact that some people feel some signs of mountain sickness already at relatively low altitudes - 2100 - 2400 m, others are resistant to them up to 4200 - 4500 m, but when climbing to a height of 5800 - 6000 m signs of altitude sickness, expressed in varying degrees, appear in almost all people.

The development of mountain sickness is also affected by some climatic and geographical factors: increased solar radiation, low air humidity, prolonged low temperatures and their sharp difference between night and day, strong winds, and the degree of electrization of the atmosphere. Since these factors depend, in turn, on the latitude of the area, remoteness from water spaces, and similar reasons, the same height in different mountainous regions of the country has a different effect on the same person. For example, in the Caucasus, signs of mountain sickness can appear already at altitudes of 3000-3500 m, in Altai, Fann mountains and Pamir-Alai - 3700 - 4000 m, Tien Shan - 3800-4200 m and Pamir - 4500-5000 m.

Signs and effects of altitude sickness

Altitude sickness can manifest itself suddenly, especially in cases where a person in a short period of time has significantly exceeded the boundaries of his individual tolerance, experienced excessive overstrain in conditions of oxygen starvation. However, most mountain sickness develops gradually. Its first signs are general fatigue, which does not depend on the amount of work performed, apathy, muscle weakness, drowsiness, malaise, dizziness. If a person continues to remain at a height, then the symptoms of the disease increase: digestion is disturbed, frequent nausea and even vomiting are possible, respiratory rhythm disorder, chills and fever appear. The recovery process is rather slow.

In the early stages of the development of the disease, no special treatment measures are required. Most often, after active work and proper rest, the symptoms of the disease disappear - this indicates the onset of acclimatization. Sometimes the disease continues to progress, passing into the second stage - chronic. Its symptoms are the same, but expressed to a much stronger degree: the headache can be extremely acute, drowsiness is more pronounced, the vessels of the hands are full of blood, nosebleeds are possible, shortness of breath is pronounced, the chest becomes wide, barrel-shaped, increased irritability is observed, it is possible loss of consciousness. These signs indicate a serious illness and the need for urgent transportation of the patient down. Sometimes the listed manifestations of the disease are preceded by a stage of excitation (euphoria), which is very reminiscent of alcohol intoxication.

The mechanism of the development of mountain sickness is associated with insufficient blood oxygen saturation, which affects the functions of many internal organs and systems. Of all the tissues of the body, the nervous one is the most sensitive to oxygen deficiency. In a person who got to a height of 4000 - 4500 m and prone to mountain sickness, as a result of hypoxia, arousal first arises, expressed in the appearance of a feeling of complacency and own strength. He becomes cheerful, talkative, but at the same time loses control over his actions, cannot really assess the situation. After a while, a period of depression sets in. Gaiety is replaced by sullenness, grumpiness, even pugnacity, and even more dangerous bouts of irritability. Many of these people do not rest in a dream: the dream is restless, accompanied by fantastic dreams that are in the nature of bad forebodings.

At high altitudes, hypoxia has a more serious effect on the functional state of higher nerve centers, causing dulling of sensitivity, impaired judgment, loss of self-criticism, interest and initiative, and sometimes memory loss. The speed and accuracy of the reaction noticeably decreases, as a result of the weakening of the processes of internal inhibition, the coordination of movement is upset. Mental and physical depression appears, expressed in slowness of thinking and actions, a noticeable loss of intuition and the ability to think logically, and a change in conditioned reflexes. However, at the same time, a person believes that his consciousness is not only clear, but also unusually sharp. He continues to do what he was doing before the severe effects of hypoxia on him, despite the sometimes dangerous consequences of his actions.

The sick person may develop an obsession, a sense of the absolute correctness of his actions, intolerance of critical remarks, and this, if the head of the group, a person responsible for the lives of other people, is in such a state, becomes especially dangerous. It has been observed that under the influence of hypoxia, people often do not make any attempts to get out of a clearly dangerous situation.

It is important to know what are the most common changes in human behavior that occur at altitude under the influence of hypoxia. In terms of frequency of occurrence, these changes are arranged in the following sequence:

Disproportionately large efforts in the performance of the task;

More critical attitude towards other participants of the trip;

Unwillingness to do mental work;

Increased irritability of the senses;

Touchiness;

Irritability with comments on work;

Difficulty concentrating;

Slow thinking;

Frequent, obsessive return to the same topic;

Difficulty in remembering.

As a result of hypoxia, thermoregulation can also be disturbed, due to which, in some cases, at low temperatures, the production of heat by the body decreases, and at the same time, its loss through the skin increases. Under these conditions, a person with mountain sickness is more susceptible to cooling than other participants in the trip. In other cases, chills and an increase in body temperature by 1-1.5 ° C are possible.

Hypoxia also affects many other organs and systems of the body.

Respiratory system.

If at rest a person at a height does not experience shortness of breath, lack of air or difficulty breathing, then during physical exertion at high altitude, all these phenomena begin to be noticeably felt. For example, one of the participants in climbing Everest took 7-10 full breaths and exhalations for each step at an altitude of 8200 meters. But even with such a slow pace of movement, he rested for up to two minutes every 20-25 meters of the path. Another participant of the ascent in one hour of movement, while being at an altitude of 8500 meters, climbed along a fairly easy section to a height of only about 30 meters.

Working capacity.

It is well known that any muscle activity, and especially intense, is accompanied by an increase in blood supply to the working muscles. However, if the body can provide the necessary amount of oxygen relatively easily under the conditions of the plain, then with the ascent to a great height, even with the maximum use of all adaptive reactions, the supply of oxygen to the muscles is disproportionate to the degree of muscle activity. As a result of this discrepancy, oxygen starvation develops, and under-oxidized metabolic products accumulate in the body in excess quantities. Therefore, human performance decreases sharply with increasing height. So (according to E. Gippenreiter) at an altitude of 3000 m it is 90%, at an altitude of 4000 m. -80%, 5500 m- 50%, 6200 m- 33% and 8000 m- 15-16% of the maximum level of work done at sea level.

Even at the end of work, despite the cessation of muscle activity, the body continues to be in tension, consuming an increased amount of oxygen for some time in order to eliminate oxygen debt. It should be noted that the time during which this debt is liquidated depends not only on the intensity and duration of muscle work, but also on the degree of training of a person.

The second, although less important reason for the decrease in the body's performance is the overload of the respiratory system. It is the respiratory system, by strengthening its activity up to a certain time, that can compensate for the sharply increasing oxygen demand of the body in a rarefied air environment.

Table 1

However, the possibilities of pulmonary ventilation have their own limit, which the body reaches before the maximum working capacity of the heart occurs, which reduces the required amount of oxygen consumed to a minimum. Such restrictions are explained by the fact that a decrease in the partial pressure of oxygen leads to an increase in pulmonary ventilation, and, consequently, to an increased "washout" of CO 2 from the body. But a decrease in the partial pressure of CO 2 reduces the activity of the respiratory center and thereby limits the volume of pulmonary ventilation.

At altitude, pulmonary ventilation reaches the limit values ​​already when the load is average for normal conditions. Therefore, the maximum amount of intensive work for a certain time that a tourist can perform in high mountains is less, and the recovery period after working in the mountains is longer than at sea level. However, with a long stay at the same altitude (up to 5000-5300 m) due to the acclimatization of the body, the level of working capacity increases.

The digestive system.

At altitude, appetite changes significantly, the absorption of water and nutrients decreases, the secretion of gastric juice decreases, the functions of the digestive glands change, which leads to disruption of the processes of digestion and absorption of food, especially fats. As a result, a person loses weight dramatically. So, during one of the expeditions to Everest, climbers who lived at an altitude of more than 6000 m within 6-7 weeks, lost in weight from 13.6 to 22.7 kg. At a height, a person can feel an imaginary feeling of fullness in the stomach, bursting in the epigastric region, nausea, diarrhea that is not amenable to drug treatment.

Vision.

At altitudes of about 4500 m normal visual acuity is possible only at a brightness 2.5 times greater than normal for flat conditions. At these heights, there is a narrowing of the peripheral field of vision and a noticeable "fogging" of vision in general. At high altitudes, the accuracy of fixing the gaze and the correctness of determining the distance also decrease. Even in mid-mountain conditions, vision weakens at night, and the period of adaptation to darkness lengthens.

pain sensitivity

as hypoxia increases, it decreases up to its complete loss.

Dehydration of the body.

The excretion of water from the body, as is known, is carried out mainly by the kidneys (1.5 liters of water per day), skin (1 liter), lungs (about 0.4 l) and intestines (0.2-0.3 l). It has been established that the total water consumption in the body, even in a state of complete rest, is 50-60 G at one o'clock. With average physical activity in normal climatic conditions at sea level, water consumption increases to 40-50 grams per day for every kilogram of human weight. In total, on average, under normal conditions, about 3 l water. With increased muscular activity, especially in hot conditions, the release of water through the skin sharply increases (sometimes up to 4-5 liters). But intense muscular work performed in high altitude conditions, due to lack of oxygen and dry air, sharply increases pulmonary ventilation and thereby increases the amount of water released through the lungs. All this leads to the fact that the total loss of water for participants in difficult high-mountain trips can reach 7-10 l per day.

Statistics show that in high altitude conditions more than doubles morbidity of the respiratory system. Inflammation of the lungs often takes on a croupous form, proceeds much more severely, and the resorption of inflammatory foci is much slower than in plain conditions.

Inflammation of the lungs begins after physical overwork and hypothermia. In the initial stage, there is a feeling of poor health, some shortness of breath, rapid pulse, cough. But after about 10 hours, the patient's condition deteriorates sharply: the respiratory rate is over 50, the pulse is 120 per minute. Despite taking sulfonamides, pulmonary edema develops already after 18-20 hours, which is a great danger in high altitude conditions. The first signs of acute pulmonary edema: dry cough, complaints of pressure slightly below the sternum, shortness of breath, weakness during exercise. In serious cases, there is hemoptysis, suffocation, severe confusion, followed by death. The course of the disease often does not exceed one day.

The basis for the formation of pulmonary edema at altitude is, as a rule, the phenomenon of increased permeability of the walls of the pulmonary capillaries and alveoli, as a result of which foreign substances (protein masses, blood elements and microbes) penetrate into the alveoli of the lungs. Therefore, the useful capacity of the lungs is sharply reduced in a short time. The hemoglobin of arterial blood, washing the outer surface of the alveoli, filled not with air, but with protein masses and blood elements, cannot be adequately saturated with oxygen. As a result, from insufficient (below the permissible norm) supply of oxygen to body tissues, a person quickly dies.

Therefore, even in case of the slightest suspicion of a respiratory disease, the group must immediately take measures to bring the sick person down as soon as possible, preferably to an altitude of about 2000-2500 meters.

The mechanism of development of mountain sickness

Dry atmospheric air contains: 78.08% nitrogen, 20.94% oxygen, 0.03% carbon dioxide, 0.94% argon and 0.01% other gases. When rising to a height, this percentage does not change, but the density of the air changes, and, consequently, the magnitude of the partial pressures of these gases.

According to the law of diffusion, gases pass from an environment with a higher partial pressure to an environment with a lower pressure. Gas exchange, both in the lungs and in human blood, is carried out due to the existing difference in these pressures.

At normal atmospheric pressure 760 mmp t. st. partial pressure of oxygen is:

760x0.2094=159 mmHg Art., where 0.2094 is the percentage of oxygen in the atmosphere, equal to 20.94%.

Under these conditions, the partial pressure of oxygen in the alveolar air (inhaled with air and entering the alveoli of the lungs) is about 100 mmHg Art. Oxygen is poorly soluble in blood, but it binds to the hemoglobin protein found in red blood cells - erythrocytes. Under normal conditions, due to the high partial pressure of oxygen in the lungs, hemoglobin in arterial blood is saturated with oxygen up to 95%.

When passing through the capillaries of tissues, hemoglobin in the blood loses about 25% of oxygen. Therefore, venous blood carries up to 70% oxygen, the partial pressure of which, as can be easily seen from the graph (Fig. 2), is

0 10 20 30 40 50 60 70 80 90 100

Partial pressure of oxygen mm .pm .cm.

Rice. 2.

at the time of the flow of venous blood to the lungs at the end of the circulatory cycle, only 40 mmHg Art. Thus, there is a significant pressure difference between venous and arterial blood, equal to 100-40=60 mmHg Art.

Between carbon dioxide inhaled with air (partial pressure 40 mmHg Art.), and carbon dioxide flowing with venous blood to the lungs at the end of the circulatory cycle (partial pressure 47-50 mmHg.), differential pressure is 7-10 mmHg Art.

As a result of the existing pressure drop, oxygen passes from the pulmonary alveoli into the blood, and directly in the tissues of the body, this oxygen diffuses from the blood into the cells (into an environment with an even lower partial pressure). Carbon dioxide, on the contrary, first passes from the tissues into the blood, and then, when venous blood approaches the lungs, from the blood into the alveoli of the lung, from where it is exhaled into the surrounding air. (Fig. 3).

Rice. 3.

With ascent to altitude, the partial pressures of gases decrease. So, at an altitude of 5550 m(corresponding to an atmospheric pressure of 380 mmHg Art.) for oxygen it is:

380x0.2094=80 mmHg Art.,

that is, it is reduced by half. At the same time, of course, the partial pressure of oxygen in the arterial blood also decreases, as a result of which not only the saturation of blood hemoglobin with oxygen decreases, but also due to a sharp reduction in the pressure difference between arterial and venous blood, the transfer of oxygen from blood to tissues worsens significantly. This is how oxygen deficiency-hypoxia occurs, which can lead to a person's illness with mountain sickness.

Naturally, a number of protective compensatory-adaptive reactions arise in the human body. So, first of all, the lack of oxygen leads to the excitation of chemoreceptors - nerve cells that are very sensitive to a decrease in the partial pressure of oxygen. Their excitation serves as a signal for deepening and then quickening of breathing. The resulting expansion of the lungs increases their alveolar surface and thereby contributes to a more rapid saturation of hemoglobin with oxygen. Thanks to this, as well as a number of other reactions, a large amount of oxygen enters the body.

However, with increased respiration, ventilation of the lungs increases, during which there is an increased excretion (“washing out”) of carbon dioxide from the body. This phenomenon is especially enhanced with the intensification of work in high altitude conditions. So, if on the plain at rest within one minute approximately 0.2 l CO 2, and during hard work - 1.5-1.7 l, then in high altitude conditions, on average, the body loses about 0.3-0.35 per minute l CO 2 at rest and up to 2.5 l during intense muscular work. As a result, there is a lack of CO 2 in the body - the so-called hypocapnia, characterized by a decrease in the partial pressure of carbon dioxide in arterial blood. But carbon dioxide plays an important role in regulating the processes of respiration, circulation and oxidation. A serious lack of CO 2 can lead to paralysis of the respiratory center, to a sharp drop in blood pressure, deterioration of the heart, and disruption of nervous activity. Thus, a decrease in CO 2 blood pressure by 45 to 26 mm. r t. reduces blood circulation to the brain by almost half. That is why cylinders intended for breathing at high altitudes are filled not with pure oxygen, but with its mixture with 3-4% carbon dioxide.

A decrease in the content of CO 2 in the body disrupts the acid-base balance towards an excess of alkalis. Trying to restore this balance, the kidneys intensively remove this excess of alkalis from the body along with urine for several days. Thus, acid-base balance is achieved at a new, lower level, which is one of the main signs of the completion of the adaptation period (partial acclimatization). But at the same time, the value of the alkaline reserve of the body is violated (decreases). In case of mountain sickness, a decrease in this reserve contributes to its further development. This is explained by the fact that a rather sharp decrease in the amount of alkalis reduces the ability of the blood to bind acids (including lactic acid) that are formed during hard work. This in a short time changes the acid-base ratio in the direction of an excess of acids, which disrupts the work of a number of enzymes, leads to disorganization of the metabolic process and, most importantly, inhibition of the respiratory center occurs in a seriously ill patient. As a result, breathing becomes shallow, carbon dioxide is not completely removed from the lungs, accumulates in them and prevents oxygen from reaching hemoglobin. At the same time, suffocation quickly sets in.

From all that has been said, it follows that although the main cause of mountain sickness is a lack of oxygen in the tissues of the body (hypoxia), the lack of carbon dioxide (hypocapnia) also plays a rather large role here.

Acclimatization

With a long stay at a height in the body, a number of changes occur, the essence of which is to preserve the normal functioning of a person. This process is called acclimatization. Acclimatization is the sum of adaptive-compensatory reactions of the body, as a result of which a good general condition is maintained, weight constancy, normal working capacity and the normal course of psychological processes are maintained. Distinguish between complete and incomplete, or partial, acclimatization.

Due to the relatively short period of stay in the mountains, mountain tourists and climbers are characterized by partial acclimatization and adaptation-short-term(as opposed to the final or long-term) adaptation of the body to new climatic conditions.

In the process of adaptation to a lack of oxygen in the body, the following changes occur:

Since the cerebral cortex is extremely sensitive to oxygen deficiency, the body in high altitude conditions primarily seeks to maintain proper oxygen supply to the central nervous system by reducing the oxygen supply to other, less important organs;

The respiratory system is also largely sensitive to a lack of oxygen. The respiratory organs react to the lack of oxygen first by deeper breathing (increasing its volume):

table 2

and then an increase in the frequency of breathing:

As a result of some reactions caused by oxygen deficiency, not only the number of erythrocytes (red blood cells containing hemoglobin) increases in the blood, but also the amount of hemoglobin itself (Fig. 4).

All this causes an increase in the oxygen capacity of the blood, that is, the ability of the blood to carry oxygen to the tissues and thus supply the tissues with the necessary amount of it increases. It should be noted that the increase in the number of erythrocytes and the percentage of hemoglobin is more pronounced if the ascent is accompanied by an intense muscle load, that is, if the adaptation process is active. The degree and rate of growth in the number of erythrocytes and hemoglobin content also depend on the geographical features of certain mountainous regions.

Increases in the mountains and the total amount of circulating blood. However, the load on the heart does not increase, since at the same time there is an expansion of capillaries, their number and length increase.

In the first days of a person's stay in high mountains (especially in poorly trained people), the minute volume of the heart increases, and the pulse increases. So, for physically poorly trained climbers at a height 4500m pulse increases by an average of 15, and at an altitude of 5500 m - at 20 beats per minute.

At the end of the acclimatization process at altitudes up to 5500 m all of these parameters are reduced to normal values, typical for normal activities at low altitudes. The normal functioning of the gastrointestinal tract is also restored. However, at high altitudes (more than 6000 m) pulse, respiration, the work of the cardiovascular system never decrease to a normal value, because here some organs and systems of a person are constantly under conditions of a certain tension. So, even during sleep at altitudes of 6500-6800 m the pulse rate is about 100 beats per minute.

It is quite obvious that for each person the period of incomplete (partial) acclimatization has a different duration. It occurs much faster and with less functional deviations in physically healthy people aged 24 to 40 years. But in any case, a 14-day stay in the mountains under conditions of active acclimatization is sufficient for a normal organism to adapt to new climatic conditions.

To eliminate the likelihood of a serious illness with mountain sickness, as well as to reduce the time of acclimatization, the following set of measures can be recommended, carried out both before leaving for the mountains and during the trip.

Before a long alpine journey, including passes above 5000 m in the route of its route m, all candidates must be subjected to a special medical-physiological examination. Persons who do not tolerate oxygen deficiency, are physically insufficiently prepared, and who have suffered pneumonia, tonsillitis or serious influenza during the pre-trek training period, should not be allowed to participate in such trips.

The period of partial acclimatization can be shortened if the participants of the upcoming trip, a few months before going to the mountains, start regular general physical training, especially to increase the endurance of the body: long-distance running, swimming, underwater sports, skating and skiing. During such training, a temporary lack of oxygen occurs in the body, which is the higher, the greater the intensity and duration of the load. Since the body works here in conditions that are somewhat similar in terms of oxygen deficiency to staying at a height, a person develops an increased resistance of the body to a lack of oxygen when performing muscular work. In the future, in mountainous conditions, this will facilitate adaptation to height, speed up the process of adaptation, and make it less painful.

You should know that for tourists who are physically unprepared for a high-mountain trip, the vital capacity of the lungs at the beginning of the trip even slightly decreases, the maximum performance of the heart (compared to trained participants) also becomes 8-10% less, and the reaction of increasing hemoglobin and erythrocytes with oxygen deficiency is delayed .

The following activities are carried out directly during the trip: active acclimatization, psychotherapy, psychoprophylaxis, organization of appropriate nutrition, the use of vitamins and adaptogens (drugs that increase the body's performance), complete cessation of smoking and alcohol, systematic condition control health, the use of certain drugs.

Active acclimatization for climbing ascents and for high-mountain hiking trips has a difference in the methods of its implementation. This difference is explained, first of all, by a significant difference in the heights of the climbing objects. So, if for climbers this height can be 8842 m, then for the most prepared tourist groups it will not exceed 6000-6500 m(several passes in the region of the High Wall, Zaalai and some other ridges in the Pamirs). The difference lies in the fact that climbing to the peaks along technically difficult routes takes place over several days, and along difficult traverses - even weeks (without significant loss of height at certain intermediate stages), while in high-mountain hiking trips that have, as a rule, a greater length, it takes less time to overcome the passes.

Lower heights, shorter stay on these W- honeycombs and a faster descent with a significant loss of altitude to a greater extent facilitate the process of acclimatization for tourists, and quite multiple the alternation of ascents and descents softens, and even stops the development of mountain sickness.

Therefore, climbers during high-altitude ascents are forced at the beginning of the expedition to allocate up to two weeks for training (acclimatization) ascents to lower peaks, which differ from the main object of climbing to a height of about 1000 meters. For tourist groups, whose routes pass through passes with a height of 3000-5000 m, special acclimatization exits are not required. For this purpose, as a rule, it is enough to choose such a route route, in which during the first week - 10 days the height of the passes passed by the group would increase gradually.

Since the greatest malaise caused by the general fatigue of a tourist who has not yet become involved in hiking life is usually felt in the first days of the hike, even when organizing a day trip at this time, it is recommended to conduct classes on movement technique, on the construction of snow huts or caves, as well as exploration or training exits. to height. These practical exercises and exits should be carried out at a good pace, which makes the body react faster to rarefied air, more actively adapt to changes in climatic conditions. N. Tenzing's recommendations are interesting in this regard: at a height, even at a bivouac, you need to be physically active - warm snow water, monitor the condition of the tents, check equipment, move more, for example, after setting up the tents, take part in the construction of a snow kitchen, help distribute prepared food by tents.

Proper nutrition is also essential in the prevention of mountain sickness. At an altitude of over 5000 m the daily diet should have at least 5000 large calories. The content of carbohydrates in the diet should be increased by 5-10% compared to the usual diet. In areas associated with intense muscle activity, first of all, an easily digestible carbohydrate - glucose should be consumed. Increased carbohydrate intake contributes to the formation of more carbon dioxide, which the body lacks. The amount of fluid consumed in high altitude conditions and, especially, when performing intensive work associated with movement along difficult sections of the route, should be at least 4-5 l per day. This is the most decisive measure in the fight against dehydration. In addition, an increase in the volume of fluid consumed contributes to the removal of underoxidized metabolic products from the body through the kidneys.

The body of a person who prolonged intensive work in high altitude conditions requires an increased (2-3 times) amount of vitamins, especially those that are part of the enzymes involved in the regulation of redox processes and are closely related to metabolism. These are B vitamins, where B 12 and B 15 are the most important, as well as B 1, B 2 and B 6. So, vitamin B 15, in addition to the above, helps to increase the body's performance at altitude, greatly facilitating the performance of large and intense loads, increases the efficiency of oxygen use, activates oxygen metabolism in tissue cells, and increases altitude stability. This vitamin enhances the mechanism of active adaptation to a lack of oxygen, as well as fat oxidation at altitude.

In addition to them, vitamins C, PP and folic acid in combination with iron glycerophosphate and metacil also play an important role. Such a complex has an effect on an increase in the number of red blood cells and hemoglobin, that is, an increase in the oxygen capacity of the blood.

The acceleration of adaptation processes is also influenced by the so-called adaptogens - ginseng, eleutherococcus and acclimatizin (a mixture of eleutherococcus, lemongrass and yellow sugar). E. Gippenreiter recommends the following complex of drugs that increase the body's adaptability to hypoxia and facilitate the course of mountain sickness: eleutherococcus, diabazole, vitamins A, B 1, B 2, B 6, B 12, C, PP, calcium pantothenate, methionine, calcium gluconate, calcium glycerophosphate and potassium chloride. The mixture proposed by N. Sirotinin is also effective: 0.05 g of ascorbic acid, 0.5 G. citric acid and 50 g of glucose per dose. We can also recommend a dry blackcurrant drink (in briquettes of 20 G), containing citric and glutamic acids, glucose, sodium chloride and phosphate.

How long, upon returning to the plain, does the organism retain the changes that have occurred in it during the process of acclimatization?

At the end of the journey in the mountains, depending on the altitude of the route, the changes acquired in the process of acclimatization in the respiratory system, blood circulation and the composition of the blood itself pass quickly enough. So, the increased content of hemoglobin decreases to normal in 2-2.5 months. Over the same period, the increased ability of the blood to carry oxygen also decreases. That is, the acclimatization of the body to the height lasts only up to three months.

True, after repeated trips to the mountains, a kind of “memory” is developed in the body for adaptive reactions to altitude. Therefore, at the next trip to the mountains, its organs and systems, already along the “beaten paths”, quickly find the right way to adapt the body to a lack of oxygen.

Help for mountain sickness

If, despite the measures taken, any of the participants in the high-mountain hike shows symptoms of altitude sickness, it is necessary:

For headaches, take Citramon, Pyramidone (no more than 1.5 g per day), Analgin (no more than 1 G for a single dose and 3 g per day) or their combinations (troychatka, quintuple);

With nausea and vomiting - Aeron, sour fruits or their juices;

For insomnia - noxiron, when a person falls asleep badly, or Nembutal, when sleep is not deep enough.

When using drugs in high altitude conditions, special care should be taken. First of all, this applies to biologically active substances (phenamine, phenatin, pervitin), which stimulate the activity of nerve cells. It should be remembered that these substances create only a short-term effect. Therefore, it is better to use them only when absolutely necessary, and even then already during the descent, when the duration of the upcoming movement is not long. An overdose of these drugs leads to exhaustion of the nervous system, to a sharp decrease in efficiency. An overdose of these drugs is especially dangerous in conditions of prolonged oxygen deficiency.

If the group decided to urgently descend the sick participant, then during the descent it is necessary not only to systematically monitor the patient's condition, but also regularly inject antibiotics and drugs that stimulate the human heart and respiratory activity (lobelia, cardiamine, corazol or norepinephrine).

SUN EXPOSURE

Sun burns.

From prolonged exposure to the sun on the human body, sunburns form on the skin, which can cause a painful condition for a tourist.

Solar radiation is a stream of rays of the visible and invisible spectrum, which have different biological activity. When exposed to the sun, there is a simultaneous effect of:

Direct solar radiation;

Scattered (arrived due to the scattering of part of the flow of direct solar radiation in the atmosphere or reflection from clouds);

Reflected (as a result of the reflection of rays from surrounding objects).

The magnitude of the flow of solar energy falling on one or another specific area of ​​​​the earth's surface depends on the height of the sun, which, in turn, is determined by the geographical latitude of this area, the time of year and day.

If the sun is at its zenith, then its rays travel the shortest path through the atmosphere. At a standing height of the sun of 30 °, this path doubles, and at sunset - 35.4 times more than with a sheer fall of the rays. Passing through the atmosphere, especially through its lower layers containing particles of dust, smoke and water vapor in suspension, the sun's rays are absorbed and scattered to a certain extent. Therefore, the greater the path of these rays through the atmosphere, the more polluted it is, the lower the intensity of solar radiation they have.

With the rise to a height, the thickness of the atmosphere through which the sun's rays pass decreases, and the most dense, moistened and dusty lower layers are excluded. Due to the increase in the transparency of the atmosphere, the intensity of direct solar radiation increases. The nature of the change in intensity is shown in the graph (Fig. 5).

Here, the flux intensity at sea level is taken as 100%. The graph shows that the amount of direct solar radiation in the mountains increases significantly: by 1-2% with an increase for every 100 meters.

The total intensity of the direct solar radiation flux, even at the same height of the sun, changes its value depending on the season. Thus, in summer, due to an increase in temperature, increasing humidity and dust reduce the transparency of the atmosphere to such an extent that the magnitude of the flux at a sun height of 30 ° is 20% less than in winter.

However, not all components of the spectrum of sunlight change their intensity to the same extent. The intensity increases especially ultraviolet rays are the most active physiologically: it has a pronounced maximum at a high position of the sun (at noon). The intensity of these rays during this period in the same weather conditions is the time required for

redness of the skin, at a height of 2200 m 2.5 times, and at an altitude of 5000 m 6 times less than at an altitude of 500 winds (Fig. 6). With a decrease in the height of the sun, this intensity drops sharply. So, for a height of 1200 m this dependence is expressed by the following table (the intensity of ultraviolet rays at a sun height of 65 ° is taken as 100%):

Table4

If the clouds of the upper tier weaken the intensity of direct solar radiation, usually only to an insignificant extent, then the denser clouds of the middle and especially the lower tiers can reduce to zero. .

Diffused radiation plays a significant role in the total amount of incoming solar radiation. Scattered radiation illuminates places that are in the shade, and when the sun closes over some area with dense clouds, it creates a general daylight illumination.

The nature, intensity and spectral composition of scattered radiation are related to the height of the sun, the transparency of the air and the reflectivity of clouds.

Scattered radiation in a clear sky without clouds, caused mainly by atmospheric gas molecules, differs sharply in its spectral composition both from other types of radiation and from scattered radiation under a cloudy sky. The maximum energy in its spectrum is shifted to shorter wavelengths. And although the intensity of scattered radiation in a cloudless sky is only 8-12% of the intensity of direct solar radiation, the abundance of ultraviolet rays in the spectral composition (up to 40-50% of the total number of scattered rays) indicates its significant physiological activity. The abundance of short-wavelength rays also explains the bright blue color of the sky, the blueness of which is the more intense, the cleaner the air.

In the lower layers of the air, when the sun's rays are scattered from large suspended particles of dust, smoke and water vapor, the intensity maximum shifts to the region of longer waves, as a result of which the color of the sky becomes whitish. With a whitish sky or in the presence of a weak fog, the total intensity of scattered radiation increases by 1.5-2 times.

When clouds appear, the intensity of scattered radiation increases even more. Its value is closely related to the amount, shape and location of clouds. So, if at a high standing of the sun the sky is covered by clouds by 50-60%, then the intensity of scattered solar radiation reaches values ​​equal to the flow of direct solar radiation. With a further increase in cloudiness and especially with its compaction, the intensity decreases. With cumulonimbus clouds, it can even be lower than with a cloudless sky.

It should be borne in mind that if the flux of scattered radiation is higher, the lower the transparency of the air, then the intensity of ultraviolet rays in this type of radiation is directly proportional to the transparency of the air. In the daily course of changes in illumination, the greatest value of scattered ultraviolet radiation falls on the middle of the day, and in the annual course - in winter.

The value of the total flux of scattered radiation is also influenced by the energy of the rays reflected from the earth's surface. So, in the presence of pure snow cover, scattered radiation increases by 1.5-2 times.

The intensity of reflected solar radiation depends on the physical properties of the surface and on the angle of incidence of the sun's rays. Wet black soil reflects only 5% of the rays falling on it. This is because the reflectivity decreases significantly with increasing soil moisture and roughness. But alpine meadows reflect 26%, polluted glaciers - 30%, clean glaciers and snowy surfaces - 60-70%, and freshly fallen snow - 80-90% of the incident rays. Thus, when moving in the highlands along snow-covered glaciers, a person is affected by a reflected stream, which is almost equal to direct solar radiation.

The reflectivity of individual rays included in the spectrum of sunlight is not the same and depends on the properties of the earth's surface. So, water practically does not reflect ultraviolet rays. The reflection of the latter from the grass is only 2-4%. At the same time, for freshly fallen snow, the reflection maximum is shifted to the short-wavelength range (ultraviolet rays). You should know that the number of ultraviolet rays reflected from the earth's surface, the greater, the brighter this surface. It is interesting to note that the reflectivity of human skin for ultraviolet rays is on average 1-3%, that is, 97-99% of these rays falling on the skin are absorbed by it.

Under normal conditions, a person is faced not with one of the listed types of radiation (direct, diffuse or reflected), but with their total effect. On the plain, this total exposure under certain conditions can be more than twice the intensity of exposure to direct sunlight. When traveling in the mountains at medium altitudes, the irradiation intensity as a whole can be 3.5-4 times, and at an altitude of 5000-6000 m 5-5.5 times higher than normal flat conditions.

As has already been shown, with increasing altitude, the total flux of ultraviolet rays especially increases. At high altitudes, their intensity can reach values ​​exceeding the intensity of ultraviolet irradiation with direct solar radiation in plain conditions by 8-10 times!

Influencing open areas of the human body, ultraviolet rays penetrate the human skin to a depth of only 0.05 to 0.5 mm, causing, at moderate doses of radiation, redness, and then darkening (sunburn) of the skin. In the mountains, open areas of the body are exposed to solar radiation throughout the daylight hours. Therefore, if the necessary measures are not taken in advance to protect these areas, a body burn can easily occur.

Outwardly, the first signs of burns associated with solar radiation do not correspond to the degree of damage. This degree comes to light a little later. According to the nature of the lesion, burns are generally divided into four degrees. For the considered sunburns, in which only the upper layers of the skin are affected, only the first two (the mildest) degrees are inherent.

I - the mildest degree of burn, characterized by reddening of the skin in the burn area, swelling, burning, pain and some development of skin inflammation. Inflammatory phenomena pass quickly (after 3-5 days). Pigmentation remains in the burn area, sometimes peeling of the skin is observed.

II degree is characterized by a more pronounced inflammatory reaction: intense reddening of the skin and exfoliation of the epidermis with the formation of blisters filled with a clear or slightly cloudy liquid. Full recovery of all layers of the skin occurs in 8-12 days.

Burns of the 1st degree are treated by skin tanning: the burnt areas are moistened with alcohol, a solution of potassium permanganate. In the treatment of second degree burns, the primary treatment of the burn site is performed: rubbing with gasoline or 0.5%. ammonia solution, irrigation of the burnt area with antibiotic solutions. Considering the possibility of introducing an infection in field conditions, it is better to close the burn area with an aseptic bandage. A rare change of dressing contributes to the speedy recovery of the affected cells, since the layer of delicate young skin is not injured.

During a mountain or ski trip, the neck, earlobes, face and skin of the outer side of the hands suffer most from exposure to direct sunlight. As a result of exposure to scattered, and when moving through the snow and reflected rays, the chin, lower part of the nose, lips, skin under the knees are burned. Thus, almost any open area of ​​the human body is prone to burns. On warm spring days, when driving in the highlands, especially in the first period, when the body is not yet tanned, in no case should one allow a long (over 30 minutes) exposure to the sun without a shirt. The delicate skin of the abdomen, lower back and lateral surfaces of the chest are most sensitive to ultraviolet rays. It is necessary to strive to ensure that in sunny weather, especially in the middle of the day, all parts of the body are protected from exposure to all types of sunlight. In the future, with repeated repeated exposure to ultraviolet radiation, the skin acquires a tan and becomes less sensitive to these rays.

The skin of the hands and face is the least susceptible to UV rays.

Rice. 7

But due to the fact that it is the face and hands that are the most exposed parts of the body, they suffer most from sunburn. Therefore, on sunny days, the face should be protected with a gauze bandage. In order to prevent the gauze from getting into the mouth during deep breathing, it is advisable to use a piece of wire (length 20-25 cm, diameter 3 mm), passed through the bottom of the bandage and curved in an arc (rice. 7).

In the absence of a mask, the parts of the face that are most susceptible to burns can be covered with a protective cream such as "Ray" or "Nivea", and lips with colorless lipstick. To protect the neck, it is recommended to hem double-folded gauze to the headgear from the back of the head. Take special care of your shoulders and hands. If with a burn

shoulders, the injured participant cannot carry a backpack and all his load falls on other comrades with an additional weight, then if the burns of the hands are burned, the victim will not be able to provide reliable insurance. Therefore, on sunny days, wearing a long-sleeved shirt is a must. The back of the hands (when moving without gloves) must be covered with a layer of protective cream.

snow blindness

(eye burn) occurs with a relatively short (within 1-2 hours) movement in the snow on a sunny day without goggles as a result of a significant intensity of ultraviolet rays in the mountains. These rays affect the cornea and conjunctiva of the eyes, causing them to burn. Within a few hours, pain (“sand”) and lacrimation appear in the eyes. The victim cannot look at light, even at a lit match (photophobia). There is some swelling of the mucous membrane, in the future blindness may occur, which, if timely measures are taken, disappears without a trace after 4-7 days.

To protect the eyes from burns, it is necessary to use goggles, the dark lenses of which (orange, dark purple, dark green or brown) absorb ultraviolet rays to a large extent and reduce the overall illumination of the area, preventing eye fatigue. It is useful to know that the color orange improves the feeling of relief in conditions of snowfall or light fog, creates the illusion of sunlight. Green color brightens up the contrasts between brightly lit and shady areas of the area. Since bright sunlight reflected from a white snowy surface has a strong stimulating effect on the nervous system through the eyes, wearing goggles with green lenses has a calming effect.

The use of goggles made of organic glass in high-altitude and ski trips is not recommended, since the spectrum of the absorbed part of the ultraviolet rays of such glass is much narrower, and some of these rays, which have the shortest wavelength and have the greatest physiological effect, still reach the eyes. Prolonged exposure to such, even a reduced amount of ultraviolet rays, can eventually lead to eye burns.

It is also not recommended to take canned glasses that fit snugly to the face on a hike. Not only glasses, but also the skin of the part of the face covered by them fogs up a lot, causing an unpleasant sensation. Much better is the use of conventional glasses with sidewalls made of a wide adhesive plaster. (Fig. 8).

Rice. eight.

Participants in long hikes in the mountains must always have spare glasses at the rate of one pair for three people. In the absence of spare glasses, you can temporarily use a gauze blindfold or put cardboard tape over your eyes, making pre-narrow slits in it in order to see only a limited area of ​​\u200b\u200bthe area.

First aid for snow blindness: rest for the eyes (dark bandage), washing the eyes with a 2% solution of boric acid, cold lotions from tea broth.

Sunstroke

A severe painful condition that suddenly arises during long transitions as a result of many hours of exposure to infrared rays of direct sunlight on an uncovered head. At the same time, in the conditions of the campaign, the back of the head is exposed to the greatest influence of the rays. The outflow of arterial blood that occurs in this case and a sharp stagnation of venous blood in the veins of the brain lead to its edema and loss of consciousness.

The symptoms of this disease, as well as the actions of the first aid team, are the same as those for heat stroke.

A headgear that protects the head from exposure to sunlight and, in addition, retains the possibility of heat exchange with the surrounding air (ventilation) thanks to a mesh or a series of holes, is a mandatory accessory for a participant in a mountain trip.

1. On what trajectory do the planets move around the Sun?

2. It is known that the first, second and third cosmic velocities are respectively 7.9; 11.2 and 16.5 km/s. Express these speeds in m/s and km/h.

3. What is the speed of the ISS (International Space Station) and the Soyuz-TM-31 transport spacecraft after docking relative to each other?

4. Astronauts of the Salyut-6 orbital space station observed the approach of the Progress transport spacecraft. “The speed of the ship is 4 m/s,” said Yuri Romanenko. Relative to what body did the cosmonaut mean the speed of the ship - relative to the Earth or relative to the Salyut station?

5. Imagine that four identical Earth satellites are launched from a cosmodrome located on the equator to the same height: to the north, south, west, and east. In this case, each next satellite was launched after 1 min. after the previous one. Will the satellites collide in flight? Which one was easier to run? The orbits are considered circular. (Answer:satellites launched along the equator will collide, while those launched north and south cannot collide, because they will rotate in different planes, the angle between which is equal to the angle of rotation of the Earth in 1 min. In the direction of the Earth's rotation, i.e. to the east, it is easier to launch a satellite, since this uses the speed of the Earth's rotation, which supplements the speed reported by the launch vehicle. The most difficult thing is to launch a satellite to the west ).

6. The distance between stars is usually expressed in light years. A light year is the distance traveled by light in a vacuum in one year. Express a light year in kilometers. (Answer:9.5 * 10 12 km).

7. The Andromeda Nebula is visible to the naked eye, but is 900 thousand light away from the Earth. years. Express this distance in kilometers. (Answer:8.5*10 18 km ) .

8. The speed of an artificial satellite of the Earth is 8 km / s, and rifle bullets are 800 m / s. Which of these bodies is moving faster and by how much?

9. How long does it take for light to travel from the Sun to the Earth? (Answer:8 min 20 s ).

10. The closest star to us is in the constellation Centaurus. The light from it takes 4.3 years to reach the Earth. Determine the distance to this star. (Answer:270,000 a.u. ).

11. The Soviet spacecraft "Vostok-5" with Valery Bykovsky on board circled the Earth 81 times. Calculate the distance (in AU) traveled by the ship, assuming the orbit is circular and 200 km from the Earth's surface. (Answer:0.022 AU .) .

12. The expedition of Magellan made a trip around the world in 3 years, and Gagarin circled the globe in 89 minutes. The paths traveled by them are approximately equal. How many times did Gagarin's average flight speed exceed Magellan's average swimming speed? (Answer: 20 000) .

13. The star Vega, in the direction of which our solar system is moving at a speed of 20 km / s, is located at a distance of 2.5 * 10 14 km from us. How long would it take us to be near this star if it did not itself move in world space? (Answer:in 400,000 years).

14. How far does the Earth travel when moving around the Sun in a second? per day? in a year? (Answer:30 km; 2.6 million km; 940 million km).

15. Find the average speed of the Moon around the Earth, assuming the Moon's orbit is circular. The average distance from the Earth to the Moon is 384,000 km, and 16. the period of revolution is 24 hours. (Answer:1 km/s ) .

16. How long will it take the rocket to acquire the first space velocity of 7.9 km / s if it moves with an acceleration of 40 m / s 2? (Answer:3.3 min ) .

17. What time would it take for a spaceship accelerated by a photon rocket with a constant acceleration of 9.8 m/s 2 to reach a speed equal to 9/10 of the speed of light? (Answer:320 days ) .

18. A space rocket accelerates from a state of rest and, having traveled a distance of 200 km, reaches a speed of 11 km / s. How fast was she moving? What is the acceleration time? (Answer:300 m/s 2 ; 37s ) .

19. The Soviet spacecraft-satellite "Vostok-3" with cosmonaut Andrian Nikolaev on board made 64 revolutions around the Earth in 95 hours. Determine the average flight speed (in km/s). The spacecraft's orbit is considered to be circular and 230 km away from the Earth's surface. (Answer:7.3 km/s).

20. At what distance from the Earth should the spacecraft be in order for the radio signal sent from the Earth and reflected by the ship to return to Earth 1.8 s after its departure. (Answer:270,000 km).

21. The asteroid Icarus revolves around the Sun in 1.02 years, being on average at a distance of 1.08 AU. From him. Determine the average speed of the asteroid. (Answer:31.63km/s ) .

22. The asteroid Hidalgo revolves around the Sun in 14.04 years, at an average distance of 5.82 AU. From him. Determine the average speed of the asteroid. (Answer:12.38 km/s ) .

23. Comet Schwassmann-Wachmann moves in an orbit close to circular with a period of 15.3 years at a distance of 6.09 AU. from the sun. Calculate the speed of its movement. (Answer:11.89 km/s ).

24. How long will it take the rocket to acquire the first cosmic velocity of 7.9 km/s if it moves with an acceleration of 40 m/s 2? (Answer : 3.3s).

25. A satellite, moving near the earth's surface in an elliptical orbit, is decelerated by the atmosphere. How will this change the flight path? ( Answer: Reducing the speed changes the elliptical path to a circular one. A further continuous decrease in speed transforms the circular orbit into a spiral. This explains why the first satellites existed for a limited time. Getting into the dense layers of the atmosphere, they heated up to a huge temperature and evaporated).

26. Is it possible to create a satellite that will move around the earth for an arbitrarily long time? ( Answer:Practically possible. At an altitude of about several thousand kilometers, air resistance has almost no effect on the flight of the satellite. In addition, small rockets can be installed on the satellite, which will, as needed, equalize the speed of the satellite to the desired one).

27. The human body can tolerate a fourfold increase in its weight for a relatively long time. What is the maximum acceleration that can be imparted to the spacecraft in order not to exceed this load on the body of the astronauts, if they are not equipped with means to relieve the load? To analyze cases of vertical takeoff from the Earth's surface, vertical descent, horizontal movement and flight outside the gravitational field. (Answer:According to Newton's second law, we find that with a steep start from the Earth, acceleration 3g 0 is permissible, with a steep descent 5g 0 , when moving around the Earth near its surface - g 0 , outside the gravitational field -4g 0 ).

Every organism living on our planet has its limits. What can a person endure?

How long can we live in space without a space suit?

There are many misconceptions on this topic. In fact, we can live there for a few minutes.
Let's comment on a few myths that some people still believe in:

The person will burst due to zero pressure.
Our skin is too elastic to break. Instead, our body will only swell slightly.
The person's blood boils.
In a vacuum, the boiling point of liquids is indeed lower than on Earth, but the blood will be inside the body, where the pressure will still remain.
A person will freeze due to low temperatures.
There is practically nothing in outer space, so we will simply give up our heat to nothing. But we will feel the coolness all the same, since all the moisture will evaporate from the skin.

But the lack of oxygen can kill a person in the first place. Even if we try to hold our breath, the air will still escape from our lungs with great force and speed. As a result, after 10-20 seconds the person will lose consciousness. Then, within one or two minutes, it will still be possible to save him, picking him up in time and providing the necessary medical assistance, but later not anymore.

How much electric shock can we withstand?

Electric current passing through the human body can cause two types of lesions - electric shock and electrical injury.

Electric shock is more dangerous, since it affects the entire body. Death occurs from paralysis of the heart or breathing, and sometimes from both at the same time.

Electrical injury refers to electric shock to external parts of the body; these are burns, plating of the skin, etc. Electric shocks are, as a rule, of a mixed nature and depend on the magnitude and type of current flowing through the human body, the duration of its exposure, the paths along which the current passes, and also on the physical and mental state of the person in moment of defeat.

A person begins to feel an alternating current of industrial frequency at 0.6 - 15 mA. A current of 12 - 15 mA causes severe pain in the fingers and hands. A person can withstand this state for 5-10 seconds and can independently tear his hands off the electrodes. A current of 20 - 25 mA causes very severe pain, hands become paralyzed, breathing becomes difficult, a person cannot free himself from the electrodes. At a current of 50-80 mA, respiratory paralysis occurs, and at 90-100 mA, heart paralysis and death.

How much can we eat?

Our stomach can hold 3-4 liters of food and drink. But what if you try to eat more? This is practically impossible, because in this case everything will start to come out.

However, it is quite possible to die from overeating.
To do this, you need to fill yourself with products that can enter into chemical reactions with each other, and the gas formed in this case can lead to rupture of the stomach.

How long can we stay awake?

It is known that Air Force pilots, after three or four days of wakefulness, fell into such an uncontrollable state that they crashed their planes (falling asleep at the helm). Even one night without sleep affects the ability of the driver in the same way as intoxication. The absolute limit of voluntary sleep resistance is 264 hours (about 11 days). This record was set by 17-year-old Randy Gardner for a high school science project fair in 1965. Before he fell asleep on the 11th day, he was actually a plant with open eyes.

In June of this year, a 26-year-old Chinese man died after 11 days without sleep while trying to watch all the European Championship games. At the same time, he consumed alcohol and smoked, which makes it difficult to determine the exact cause of death. But just because of lack of sleep, definitely not a single person died. And for obvious ethical reasons, scientists cannot determine this period in the laboratory.
But they were able to do it on rats. In 1999, sleep researchers at the University of Chicago placed rats on a spinning disk above a pool of water. They continuously recorded the behavior of the rats using a computer program capable of recognizing the onset of sleep. As the rat began to fall asleep, the disc would suddenly turn, awakening it, throwing it against the wall and threatening to throw it into the water. The rats typically died after two weeks of this treatment. Before death, the rodents showed symptoms of hypermetabolism, a condition in which the resting metabolic rate of the body increases so much that all excess calories are burned, even when the body is completely immobile.
Hypermetabolism is associated with lack of sleep.

How much radiation can we withstand?

Radiation is a long-term danger because it causes DNA mutations, changing the genetic code in a way that leads to cancerous cell growth. But what dose of radiation will kill you immediately? According to Peter Caracappa, a nuclear engineer and radiation safety specialist at Rensler Polytechnic Institute, a dose of 5-6 sieverts (Sv) in a few minutes will destroy too many cells for the body to cope with. "The longer the dose accumulation period, the higher the chances of survival, as the body is trying to repair itself at this time," Caracappa explained.

In comparison, some workers at Japan's Fukushima nuclear power plant received 0.4 to 1.5 sieverts of radiation in an hour while confronting the accident last March. Although they survived, their cancer risk is significantly increased, scientists say.

Even if nuclear accidents and supernova explosions are avoided, Earth's natural background radiation (from sources such as uranium in the soil, cosmic rays and medical devices) increases our chances of getting cancer in any given year by 0.025 percent, Caracappa says. This places a somewhat odd limit on human lifespan.

"The average person ... receiving an average dose of background radiation every year for 4,000 years, in the absence of other factors, will inevitably get cancer caused by radiation," Caracappa says. In other words, even if we can defeat all diseases and turn off the genetic commands that control the aging process, we still won't live beyond 4,000 years.

How much acceleration can we sustain?

The ribcage protects our heart from strong impacts, but it is not a reliable protection against jerks, which have become possible thanks to the development of technology today. What acceleration can this organ of ours withstand?

NASA and military researchers have run a series of tests in an attempt to answer this question. The purpose of these tests was the safety of structures of space and air vehicles. (We don't want astronauts to pass out when a rocket takes off.) Horizontal acceleration - a sideways jerk - has a negative effect on our insides, due to the asymmetry of the acting forces. According to a recent article published in the journal Popular Science, a horizontal acceleration of 14 g is capable of tearing our organs apart. Acceleration along the body towards the head can shift all the blood to the legs. Such a vertical acceleration of 4 to 8 g will make you unconscious. (1 g is the force of gravity that we feel on the earth's surface, at 14 g is this force of gravity on a planet 14 times more massive than ours.)

Acceleration directed forward or backward is the most favorable for the body, since in this case both the head and the heart are accelerated equally. Military "human braking" experiments in the 1940s and 1950s (essentially using rocket sleds moving all over Edwards Air Force Base in California) showed that we could brake at an acceleration of 45 g and still be alive to talk about it. With this kind of braking, moving at speeds above 1000 km per hour, you can stop in a split second, having traveled several hundred feet. When braking at 50 g, we are, according to experts, we are likely to turn into a bag of separate organs.

How long can we live without oxygen?

An ordinary person can be without air for a maximum of 5 minutes, a trained person - up to 9 minutes. Then the person begins convulsions, death occurs. The main danger that awaits a person in the absence of air for a long time is oxygen starvation of the brain, which very quickly leads to loss of consciousness and death.

Freedivers are lovers of deep diving without any equipment. They use various techniques that allow you to train your body and do without air for a long time without disastrous consequences. From such training, changes occur in the body that adapt a person to oxygen starvation - a slowdown in heart rate, an increase in hemoglobin levels, an outflow of blood from the limbs to vital organs. At a depth of more than 50 m, the alveoli * are filled with plasma, which maintains the required volume of the lungs, protecting them from compression and destruction. Researchers found similar changes in the body in pearl divers, who are able to dive to great depths and stay there from 2 to 6 minutes.

On June 3, 2012 live, German diver Tom Sitas spent more than two dozen minutes underwater in front of an astonished crowd. The record is 22 min 22 sec.

* Alveolus - the end part of the respiratory apparatus in the lung, having the form of a bubble, open into the lumen of the alveolar passage. The alveoli are involved in the act of breathing, carrying out gas exchange with the pulmonary capillaries.

What is the lethal dose of apples?

About 1.5 mg of hydrogen cyanide per kilogram of human body.

We all know that apples are healthy and tasty. However, their seeds contain a small amount of a compound that turns into the dangerous toxin hydrogen cyanide or hydrocyanic acid when digested.

An apple is estimated to contain about 700 mg of hydrogen cyanide per kilogram of dry weight, and about 1.5 mg of cyanide per kilogram of human body can kill. This means that for this you need to chew and swallow half a cup of apple seeds in one sitting.

Symptoms of mild cyanide poisoning include confusion, dizziness, headache, and vomiting. Large doses can lead to breathing problems, kidney failure and, in rare cases, death.

But none of this will happen if you do not chew and grind apple seeds, but swallow them whole. So they will pass through the digestive system without causing harm.

Compared to other mammals, we mature very slowly. According to medical criteria puberty in humans, it begins at the age of 12-13, the teenage period lasts until 17-18 years. After that, girls usually no longer add in height, and boys can grow up to about 26 years. That is, a significant part of life is allotted to us for growth and development.

Small animals grow faster, large ones slower. But even if we compare us not with rapidly growing and breeding mice, but with mammals of a more solid size, the difference is obvious. Cats and dogs live 15-20 years, but on average they reach the size of an adult animal in a year, and puberty occurs even earlier. The horse lives up to 25-30 years, and reaches full development in 4-5 years. In an elephant, which is comparable in life expectancy to a person (60-70 years), puberty occurs at 8-12 years. Finally, our closest relatives, chimpanzees, reach sexual maturity at 6-8 years old.

And in terms of the rate of growth in childhood, a person, as the authors of the article note, is more similar not to mammals, but to reptiles that grow all their lives, but very slowly. Boys and girls begin to rapidly stretch at puberty (from 12-13 years old), and before that, the increase in growth is much less noticeable.

Anthropologists from Northwestern University tried to solve the riddle of slow human growth, and they wrote in Proceedings of the National Academy of Sciences .

It turned out that with slow growth, a person pays for his large brain, which devours the lion's share of energy.

For the first time, scientists have studied in detail the development of a person from birth to adulthood, using different methods of brain scanning - PET (positron emission tomography) and MRI (magnetic resonance imaging). With these methods, they measured brain volume and glucose consumption, that is, energy expenditure. And then they compared these indicators of the brain with the growth of the body.

Until now, it was believed that the brain absorbs the most energy in a newborn baby, since the ratio of brain size to body at this moment is maximum. But researchers have now calculated that

The brain absorbs the maximum amount of glucose at the age of 4-5 years. During this period, the energy expenditure of the brain is 66% of metabolic energy at rest.

This is much more than our closest relatives, the great apes, spend on brain development.

And it turned out that during this period the growth of the body slows down greatly. It turns out that the brain simply "eats" the rest of the body, there is not enough energy for growth.

“After a certain age, it becomes difficult to determine the age of a child by his height,” notes Christopher Kuzava, the first author of the study. - We can rather judge the age by his speech and behavior. Our work has shown why this is so. When the brain develops most rapidly, the growth of the body almost stops, because the brain takes all the resources.

As the researchers explain,

at the peak of energy expenditure in the brain, the number of synapses, contacts between nerve cells, increases to the maximum.

Such a network of contacts enables a child at this age to learn a lot of things that he will need in the future.

A large brain is generally expensive for a person, and the first inconvenience that he experiences is a difficult birth, since the newborn has a large head. And in order to acquire the most complex system of contacts between neurons, the human brain needs a lot of energy (caloric food) and a long period of development. During a long childhood, a child learns a lot of different things that make a person a person, first of all, of course, he masters speech. Long childhood also dictates the peculiarities of human family relations: parents take care of the child for a long time and at the same time not only raise him, but also educate and teach.

Another detail of the life of man and great apes attracted the attention of scientists and gave rise to a hypothesis. Unlike the vast majority of mammals, women and females of higher primates live quite a long time after the end of the reproductive period, that is, after the onset of menopause. From the point of view of biology, life after reproduction is useless, as resources are spent, and reproduction does not occur.

To explain this phenomenon in humans and other higher primates.

Females who are past reproductive age begin to "work as grandmothers" and help their daughters raise their children. In doing so, they increase the survival rate of these children, increasing the chances of preserving and passing on their genes.

And children with parental and grandmotherly care can remain small and helpless for quite a long time, which gives them the opportunity to grow a big brain and develop intelligence. The circle is closed, you can read again.

INTRODUCTION

1. Give examples of cosmic physical bodies.
2. When was the first artificial earth satellite launched?
3. Who became the first cosmonaut of the Earth?
4. When did the first manned space flight take place?
5. What achievements of modern astronautics do you know about?

MECHANICAL MOVEMENT

1. On what trajectory do the planets move around the Sun?

2. It is known that the first, second and third cosmic velocities are respectively 7.9; 11.2 and 16.5 km/s. Express these speeds in m/s and km/h.

3. What is the speed of the ISS (International Space Station) and the Soyuz-TM-31 transport spacecraft after docking relative to each other?

4. Astronauts of the Salyut-6 orbital space station observed the approach of the Progress transport spacecraft. “The speed of the ship is 4 m/s,” said Yuri Romanenko. Relative to what body did the cosmonaut mean the speed of the ship - relative to the Earth or relative to the Salyut station?

5. Imagine that four identical Earth satellites are launched from a cosmodrome located on the equator to the same height: to the north, south, west, and east. In this case, each next satellite was launched after 1 min. after the previous one. Will the satellites collide in flight? Which one was easier to run? The orbits are considered circular. (Answer:satellites launched along the equator will collide, while those launched north and south cannot collide, because they will rotate in different planes, the angle between which is equal to the angle of rotation of the Earth in 1 min. In the direction of the Earth's rotation, i.e. to the east, it is easier to launch a satellite, since this uses the speed of the Earth's rotation, which supplements the speed reported by the launch vehicle. The most difficult thing is to launch a satellite to the west ).

6. The distance between stars is usually expressed in light years. A light year is the distance traveled by light in a vacuum in one year. Express a light year in kilometers. (Answer:9.5 * 10 12 km).

7. The Andromeda Nebula is visible to the naked eye, but is 900 thousand light away from the Earth. years. Express this distance in kilometers. (Answer:8.5*10 18 km ) .

8. The speed of an artificial satellite of the Earth is 8 km / s, and rifle bullets are 800 m / s. Which of these bodies is moving faster and by how much?

9. How long does it take for light to travel from the Sun to the Earth? (Answer:8 min 20 s ).

10. The closest star to us is in the constellation Centaurus. The light from it takes 4.3 years to reach the Earth. Determine the distance to this star. (Answer:270,000 a.u. ).

11. The Soviet spacecraft "Vostok-5" with Valery Bykovsky on board circled the Earth 81 times. Calculate the distance (in AU) traveled by the ship, assuming the orbit is circular and 200 km from the Earth's surface. (Answer:0.022 AU .) .

12. The expedition of Magellan made a trip around the world in 3 years, and Gagarin circled the globe in 89 minutes. The paths traveled by them are approximately equal. How many times did Gagarin's average flight speed exceed Magellan's average swimming speed? (Answer: 20 000) .

13. The star Vega, in the direction of which our solar system is moving at a speed of 20 km / s, is located at a distance of 2.5 * 10 14 km from us. How long would it take us to be near this star if it did not itself move in world space? (Answer:in 400,000 years).

14. How far does the Earth travel when moving around the Sun in a second? per day? in a year? (Answer:30 km; 2.6 million km; 940 million km).

15. Find the average speed of the Moon around the Earth, assuming the Moon's orbit is circular. The average distance from the Earth to the Moon is 384,000 km, and 16. the period of revolution is 24 hours. (Answer:1 km/s ) .

16. How long will it take the rocket to acquire the first space velocity of 7.9 km / s if it moves with an acceleration of 40 m / s 2? (Answer:3.3 min ) .

17. What time would it take for a spaceship accelerated by a photon rocket with a constant acceleration of 9.8 m/s 2 to reach a speed equal to 9/10 of the speed of light? (Answer:320 days ) .

18. A space rocket accelerates from a state of rest and, having traveled a distance of 200 km, reaches a speed of 11 km / s. How fast was she moving? What is the acceleration time? (Answer:300 m/s 2 ; 37s ) .

19. The Soviet spacecraft-satellite "Vostok-3" with cosmonaut Andrian Nikolaev on board made 64 revolutions around the Earth in 95 hours. Determine the average flight speed (in km/s). The spacecraft's orbit is considered to be circular and 230 km away from the Earth's surface. (Answer:7.3 km/s).

20. At what distance from the Earth should the spacecraft be in order for the radio signal sent from the Earth and reflected by the ship to return to Earth 1.8 s after its departure. (Answer:270,000 km).

21. The asteroid Icarus revolves around the Sun in 1.02 years, being on average at a distance of 1.08 AU. From him. Determine the average speed of the asteroid. (Answer:31.63km/s ) .

22. The asteroid Hidalgo revolves around the Sun in 14.04 years, at an average distance of 5.82 AU. From him. Determine the average speed of the asteroid. (Answer:12.38 km/s ) .

23. Comet Schwassmann-Wachmann moves in an orbit close to circular with a period of 15.3 years at a distance of 6.09 AU. from the sun. Calculate the speed of its movement. (Answer:11.89 km/s ).

24. How long will it take the rocket to acquire the first cosmic velocity of 7.9 km/s if it moves with an acceleration of 40 m/s 2? (Answer : 3.3s).

25. A satellite, moving near the earth's surface in an elliptical orbit, is decelerated by the atmosphere. How will this change the flight path? ( Answer: Reducing the speed changes the elliptical path to a circular one. A further continuous decrease in speed transforms the circular orbit into a spiral. This explains why the first satellites existed for a limited time. Getting into the dense layers of the atmosphere, they heated up to a huge temperature and evaporated).

26. Is it possible to create a satellite that will move around the earth for an arbitrarily long time? ( Answer:Practically possible. At an altitude of about several thousand kilometers, air resistance has almost no effect on the flight of the satellite. In addition, small rockets can be installed on the satellite, which will, as needed, equalize the speed of the satellite to the desired one).

27. The human body can tolerate a fourfold increase in its weight for a relatively long time. What is the maximum acceleration that can be imparted to the spacecraft in order not to exceed this load on the body of the astronauts, if they are not equipped with means to relieve the load? To analyze cases of vertical takeoff from the Earth's surface, vertical descent, horizontal movement and flight outside the gravitational field. (Answer:According to Newton's second law, we find that with a steep start from the Earth, acceleration 3g 0 is permissible, with a steep descent 5g 0 , when moving around the Earth near its surface - g 0 , outside the gravitational field -4g 0 ).

WEIGHT OF TEL. DENSITY

1. Compare the mass of the Earth with the mass of the Sun.

2. Find the ratio of the mass of the Sun to the total mass of the eight large planets of the solar system. (Answer:around 740 ) .

3. The mass of the third Soviet artificial Earth satellite was 1327 kg, and the first four American satellites had the following masses: Explorer-1 -13.9 kg, Avangard-1 - 1.5 kg, Explorer-3 - 14 .1 kg ("Explorer-2" did not go into orbit), "Explorer-4" - 17.3 kg. Calculate the ratio of the mass of the third artificial satellite to the total mass of the four American satellites. (Answer: 28).

4. What body of the solar system has the largest mass?

5. An astronaut in outer space pulls on a cable, the other end of which is attached to the spacecraft. Why does the ship not acquire any significant speed towards the astronaut? ( Answer:the mass of the spacecraft is many times greater than the mass of the astronaut, so the ship additionally acquires a negligible speed ).

6. The density of the earth's crust is 2700kg / m 3, and the average density of the entire planet is 5500kg / m 3. How can this be explained? What conclusion can be drawn about the density of matter in the center of the Earth, based on these data?

THE FORCE OF UNIVERSAL GRAVITATION. GRAVITY. WEIGHTLESSNESS

1. Under the influence of what force does the direction of movement of satellites launched into circumplanetary space change?

2. The thrust force of rocket engines of a spacecraft starting vertically upwards is 350 kN, and the ship's gravity force is 100 kN. Depict these forces graphically. Scale: 1cm - 100kN.

3. An automatic station revolves around the Earth. Is the force of gravity acting on the station the same when it was on the launch pad and in orbit?

4. The mass of the self-propelled lunar rover is 840 kg. What force of gravity acted on the lunar rover when it was on the Earth and on the Moon? ( Answer: 8200 N on Earth; 1370 N on the Moon ) .

5. It is known that on the Moon a body with a mass of 1 kg is affected by a force of gravity equal to 1.62 N. Determine what will be the weight of an astronaut on the Moon, whose mass is 70 kg.

6. The largest reflecting telescope in our country with a mirror diameter of 6 m is installed in the Stavropol Territory on Mount Pastukhov, its weight is 8500 kN. Determine its mass.

7. The astronauts decided to determine the mass of the planet to which they were delivered by a rocket plane. For this purpose, they used spring scales and a kilogram weight. How did they fulfill their intention if the radius of the planet was known to them in advance from astronomical measurements? (Answer:using a spring scale, you should measure the weight of the weight on this planet. Then use the law of universal gravitation, from which we obtain:(Answer: ) .

8. At what distance from the center of the Earth is the barycenter (center of gravity) of the Earth-Moon system? (Answer:According to the law of gravity ; ) .

9. Calculate the force that presses an astronaut with a mass of 80 kg to the cabin seat: a) before the start of the ascent of the spacecraft; b) with a vertical rise in the area where the rocket moves with an acceleration of 60 m / s 2; c) when flying in orbit. (Answer:800N; 5600N; 0 ) .

10. The radius of the planet Mars is 0.53 of the radius of the Earth, and the mass is 0.11 of the mass of the Earth. How many times is the force of attraction on Mars less than the force of attraction of the same body on Earth? ( Answer: 2,55) .

11. The radius of the planet Jupiter is 11.2 Earth radii, and its mass is 318 Earth masses. How many times the force of attraction on Jupiter is greater than the force of attraction of the same body on Earth? ( Answer: 2,5) .

12. The radius of the planet Venus is 0.95 of the radius of the Earth, and the mass is 0.82 of the mass of the Earth. How many times is the force of attraction on Venus less than the force of attraction of the same body on Earth? (Answer: 1,1) .

13. The radius of the planet Saturn is 9.5 Earth radii, and the mass is 95.1 Earth masses. How many times does the force of attraction on Saturn differ from the force of attraction of the same body on Earth? (Answer:1,05) .

14. The mass of the Moon is 81 times less than the mass of the Earth. Find on the line connecting the centers of the Earth and the Moon, the point at which the forces of attraction of the Earth and the Moon, acting on the body placed at this point, are equal to each other. ( (Answer:The desired point is located from the center - the Moon at a distance of 0.1S, whereS is the distance between the centers of the Earth and the Moon ) .

15. Find at what distance from the center of the Earth the period of revolution of the satellite will be equal to 24 hours, so that the satellite can occupy a constant position relative to the rotating Earth. (Answer:42 200km).

16. The radius of one of their asteroids is r = 5km. Assume that the density of the asteroid is =5.5kg/m 3 , find the acceleration due to gravity on its surface. (Answer: 0.008m/s 2 ).

17. Calculate the acceleration of free fall on the surface of the Sun, if you know: the radius of the earth's orbit R = 1.5 * 10 8 km, the radius of the Sun r = 7 * 10 5 km and the time of revolution of the Earth around the Sun T = 1 year. (Answer:265m/s 2 ).

18. The heroes of Jules Verne's novel "From the Cannon to the Moon" flew in a projectile. The Columbiad cannon had a barrel length of 300m. Considering that for a flight to the Moon, a projectile, when fired from a barrel, would have to have a speed of at least 11.1 km / s, calculate how many times the weight of the passengers inside the barrel “increased”. The movement inside the barrel is considered to be uniformly accelerated. ( Answer: more than 20,000 times ) .

19. According to the law of universal gravitation, the Moon is attracted to both the Earth and the Sun. What is stronger and by how much? ( Answer:More than twice as strong towards the Sun).

20. How to explain the apparent contradiction between the results obtained in solving the previous problem, and the fact that the Moon remains a satellite of the Earth, not the Sun? ( Answer:The Earth and the Moon are attracted to the Sun not separately, but as one body. More precisely, the common center of gravity of the Earth-Moon system, called the barycenter, is attracted to the Sun. It revolves around the Sun in an elliptical orbit. The Earth and the Moon revolve around the barycenter, making a complete revolution in a month. According to the witty expression of the remarkable popularizer of the exact sciences Ya.I. Perelman, the Sun "does not interfere in the internal relations of the Earth and the Moon," more precisely, it almost does not interfere.)

21. Let's imagine that there are two astronauts on the Moon at the points most and least distant from the Earth. Which of them will weigh more at the moment when the Moon is on the segment connecting the centers of the Earth and the Sun? ( Answer:The Moon's diameter is small compared to its distance from the Sun. Therefore, the Sun will change the astronaut's lunar weight little. The Earth, being closer to the Moon, will have a significant impact. Therefore, an astronaut located at a point closer to the Earth will weigh less).

22. At what height above the Earth's surface will the weight of the body be three times less than on its surface? ( Answer:H=R Earth ( - 1) .

23. In 1935, a star was discovered in the constellation Cassiopeia, called the white dwarf of Kuiper. Its radius is 3300 km, and its mass exceeds the mass of the Sun by 2.8. The radius of the Sun is 3.48 * 10 5 km, and the mass is 2 * 10 30 kg.
a) What is the density of matter in a star?
b) What is the free fall acceleration on its surface?
c) How much would 1 cm 3 of terrestrial air (density 0.0013 g/cm 3) weigh on the surface of a star? The effect of the star's atmosphere is ignored.
d) If the substance of the star is homogeneous, then how much does 1 cm 3 of this substance weigh on the star itself? ( Answer: 36t/cm 3 ; 35,000km/s 2 ; 45t; 130 million tons ) .

24. Will the same body on the Earth and on the Moon stretch the dynamometer spring equally?

25. Imagine that a well has been dug through the earth, passing through its center. What would be the movement of a stone thrown into such a well? Prove that the stone would have stopped after some time if it had not been burned. Where would it stop? If a vacuum were created in the well, then the movement of the stone would continue indefinitely. However, even then this system could not be considered a perpetual motion machine. Why? (Answer: oscillatory; In the center of the Earth, the speed of the stone would be maximum. Due to the force of air resistance, the oscillations of the stone would be damped. The stone would stop at the center of the earth. It is necessary to distinguish between the perpetual motion existing in nature and the perpetual motion machine. A perpetual motion machine is a machine that performs work without reducing the reserves of the energy communicated to it. If the stone in question is forced to do work, then the kinetic energy of the stone will decrease. Therefore, it is not a perpetual motion machine. A perpetual motion machine is fundamentally impossible, and it is useless to invent it ).

26. Why don't satellites fall to Earth under the influence of gravity? (Answer:they fall, but do not have time to fall. The speed of their movement is such that, having “fallen” at what distance BC along the vertical, the satellite has time to move to the distance AB along the horizontal. As a result, it is at the same distance from the surface of the Earth as before. ).

27. Why are bodies inside a spaceship flying with the engines turned off weightless?

28. What is the error in the following statement: “Since the mass of the Sun is 300,000 times the mass of the Earth, the Sun must attract the Earth more strongly?”

29. What phenomena convince us of the existence of universal gravitation?

30. It is known that it is impossible to force a children's toy to lie down. Check whether the Roly-Vstanka will maintain a horizontal (lying) position during free fall. (When performing this experiment, it is necessary that the toy falls on something soft, otherwise it may break).

31. Is it possible to weigh on a space ship-satellite moving in a circular orbit around the Earth on a spring or lever balance? (Answer:Not).

32. Can cosmonauts, if necessary, use an ordinary medical thermometer on the Earth satellite? (Answer:Yes ).

33. To make up for the loss of air for life support at the Salyut orbital station, the Progress transport ship delivered air cylinders. Does air produce pressure on the walls of the balloon in zero gravity? Should the gas storage tank on board the station be as durable as it is on Earth? (Answer:Produces, random movement of molecules exists in a state of weightlessness. Must ).

34. If a vessel partially filled with liquid is placed inside a spaceship, what will happen to the liquid after the ship's engines are turned off? Consider two cases: for a wetting and non-wetting liquid. ( Answer:a non-wetting liquid will take the form of a sphere (if there is enough space in the vessel). The wetting liquid will spread over the entire surface of the vessel, and the shape taken by the liquid will depend on the shape of the vessel and the degree of its filling. ).

35. Does the same friction force act on an astronaut on the Moon and on Earth?

36. How would the Moon begin to move if the gravitation between the Moon and the Earth disappeared? What if the moon's orbit stopped?

37. Can an astronaut determine the verticality or horizontality of instruments using a plumb line or level during a flight in an artificial satellite? (Answer:cannot, because bodies in spaceships are in a state of weightlessness ) .

38. Body weight on the Moon is 6 times less than on Earth. Will the same effort be required to tell the speed of the lunar rover on a horizontal flat surface on the Moon and on Earth? The time during which the apparatus acquires speed and other conditions are considered the same. Ignore friction. (Answer:Equally. The force required to change the speed of a body, other things being equal, depends only on the mass of the body, which is the same both on Earth and on the Moon ).

39. What kind of clock can measure time in artificial satellites: sand, clock or spring? (Answer:spring ) .

40. Will a steel key sink in water under weightless conditions, for example, on board an orbiting space station, inside which normal atmospheric air pressure is maintained? (Answer: the key can be located at any point in the liquid, since neither gravity nor the Archimedean force acts on the key under zero gravity ) .

41. The density of foam steel (steel with gas bubbles) is almost the same as that of balsa. Such steel is obtained when, when solidified in the molten state, it contains gas bubbles. Why is it possible to obtain foam steel only in a state of weightlessness, and not in terrestrial conditions? (Answer: under terrestrial conditions, gas bubbles under the action of the Archimedean force have time to stand out from the steel before it hardens ).

42. There is a large drop of mercury on the glass. What form will it take if it, along with the glass, is placed in a spacecraft flying with the engines turned off? (Answer:spherical, because in a spacecraft flying with the engines turned off, a state of weightlessness is observed).

43. Come up with a device that allows an astronaut to walk in zero gravity, for example, on the floor or wall of an orbital station. (Answer:for example, shoes with magnetic soles, if the floor (walls) of the station or ship are made of magnetic materials ) .

44. Answer the following questions: a) How to transfer water from one vessel to another in weightlessness? b) how to heat water? c) How will weightlessness affect the process of boiling water? d) How to rotate the rocket around its axis? How to change the direction of its flight? e) How to measure body weight in zero gravity? f) How to create artificial gravity? g) Is a flywheel necessary for a reciprocating machine operating in interplanetary space? (Answer:a)Water can be squeezed out of the vessel with compressed air or by pressing on the walls of the vessel, if they are elastic. b) An alcohol lamp, a kerosene stove will not burn, because there will be no air convection, and hence no oxygen access. You can use a blowtorch, infrared rays of an electric spiral and high frequency currents. c) Because If there is no convection when the water is heated, then a number of local volumes of water will be heated to a boil. the steam, expanding, will force all the water out of the vessel before it boils. d) By means of small rockets, appropriately placed, or by changing the direction of the flow of combustion products from the main rocket. e) It is necessary to act on the body with a known elastic force (for example, a spring) and measure the acceleration received by the body. f) Bring the ship into rotation around one of its axes of symmetry. g) need ).

PRESSURE. ATMOSPHERE PRESSURE

1. What pressure was exerted on the lunar soil by an astronaut whose mass with equipment was 175 kg, and whose boot left a footprint of 410 cm 2 ? (Answer:42 kN ) .

2. It is believed that the Moon was once surrounded by an atmosphere, but gradually lost it. How can this be explained?

3. Why does an astronaut need a spacesuit?

4. The first spacewalk was made by Alexei Leonov on March 18, 1965. The pressure in the astronaut's suit was 0.4 normal atmospheric pressure. Determine the numerical value of this pressure. (Answer:40 530 Pa ) .

5. At what height above sea level is atmospheric pressure equal to the pressure in an astronaut's space suit? (Answer:5 km ) .

6. To what height on Mars will a column of mercury in a barometer rise if the pressure of its atmosphere is 0.01 of the normal atmospheric pressure of the Earth? (Answer:7.6 mm).

7. To what height will a column of mercury in a barometer rise on Venus if the pressure of its atmosphere at the surface is 90 times the normal atmospheric pressure of the Earth? (Answer:68.4 m) .

8. Is it possible to measure the air pressure inside the satellite of the Earth with a mercury barometer? an aneroid barometer?

LIQUID PRESSURE. LAW OF ARCHIMEDES

1. Does the liquid produce pressure on the walls and bottom of the vessel under weightless conditions, for example, on board a satellite? (Answer:does not produce, because the pressure of the liquid on the bottom and walls of the vessel is due to the action of gravity ) .

2. What would be the results of an experiment on the study of fluid pressure carried out in a laboratory on the lunar surface? Does liquid produce pressure on the bottom and walls of a vessel on the Moon? Why? And on Mars? (Answer:produces, but the pressure is 6 times less than on Earth; on Mars is 2.7 times less ).

3. Can an astronaut draw liquid into a pipette during a flight on a spacecraft if normal atmospheric pressure is maintained in the cabin? (Answer:Maybe ) .

4. Let's imagine that in a laboratory installed on the Moon, normal atmospheric pressure is maintained. What will be the height of the mercury column if Torricelli's experiment is carried out in such a laboratory? Will the mercury come out completely from the tube? (Answer:The height of the mercury column under these conditions will be 6 times greater and will be 456 cm, since the force of gravity on the Moon is 6 times less. Torricelli's experiment would require a tube 5 m long ) .

5. Are the laws of Pascal and Archimedes valid inside the satellite ship? (Answer:both are true ) .

6. Is the law of communicating vessels valid inside the Earth satellite ship?

7. Under terrestrial conditions, various methods are used to test an astronaut in a state of weightlessness. One of them is as follows: a person in a special spacesuit is immersed in water in which he does not sink and does not emerge. Under what condition is this possible? (Answer:gravity acting on a spacesuit with a person must be balanced by the Archimedean force ) .

8. Suppose that an experiment related to the Archimedean force is being carried out on board the lunar laboratory. What will be the results of an experiment, for example, with a stone immersed in water in such a laboratory? Wouldn't a stone float on the surface of the water, since it weighs 6 times lighter on the Moon than on Earth? (Answer:The results of the experiment will be the same as on Earth. The weight of a stone on the Moon is indeed 6 times less than on Earth, but the weight of the liquid displaced by the body is also less by the same amount. ) .

9. Will a steel key sink in water under weightless conditions, for example, on board an orbiting space station, inside which normal atmospheric air pressure is maintained? (Answer:The key can be located anywhere in the liquid, since neither gravity nor the Archimedean force acts on the key under zero gravity ).

10. The vessel is partially filled with water, which does not wet its walls. Is it possible, under weightless conditions, to pour water from this vessel into another similar vessel? (Answer:Can. You can use, for example, the phenomenon of rest inertia. To do this, it is enough to connect the vessels at the end and move them towards the vessel filled with liquid).

11. A mercury barometer is dropped, and while maintaining its vertical position it falls from a great height. If we do not take into account air resistance, then we can assume that the barometer, when falling, is in a state of weightlessness. What will it show? (Answer:under the influence of atmospheric pressure, the tube will be completely filled with mercury. so the barometer will show a pressure corresponding to the pressure of the height of the column of mercury in the tube ).

12. A ball floats in a vessel with water, half submerged in water. Will the immersion depth of the ball change if this vessel with the ball is transferred to a planet where the force of gravity is twice as strong. than on earth? (Answer:Will not change.On a planet where gravity is twice as strong as on Earth, both the weight of the water and the weight of the ball will double. Therefore, the weight of the water displaced by the ball will increase in the same way as the weight of the ball. Therefore, the depth of immersion of the ball in water will not change).

13. Suppose that in a certain area on the surface of the Moon, the hardness and density of the soil coincide with the hardness and density of the soil in a given place on Earth. Where is it easier to dig with a shovel: on Earth or on the Moon? (Answer:On the ground. It should be borne in mind that the success of the work depends on the pressure of the shovel on the ground. ).

JOB. ENERGY. LAW OF CONSERVATION OF MECHANICAL ENERGY. LAW OF CONSERVATION OF MOMENTUM.

1. An astronaut lifts samples of lunar rocks aboard a spacecraft. What work does he do in this case, if the mass of the samples is 100 kg, and the height of the rise above the surface of the moon is 5 m? (Answer:since the acceleration of free fall on the moon is 1.6 m / s 2, then the work is 800 J ).

2. The mass of the Vostok spacecraft launched into near-Earth space with the world's first cosmonaut Yu. Gagarin, 4725 kg. The height of the orbit was on average 250 km above the surface of the planet. How much work did the rocket engines do just to lift the ship to that height? Ignore the change in gravity with altitude.

3. Will the astronaut perform work while lifting objects uniformly in the spacecraft during its inertial motion, i.e. in the state of zero-gravity? when telling them speed?

4. From the sum of what types of energies does the total mechanical energy of the satellite consist?

5. What happens to the potential and kinetic energy of a satellite when moving to a higher orbit?

6. Determine the total mechanical energy of each kilogram of a spacecraft launched into near-Earth space into an orbit 300 km above the earth's surface. The kinetic energy of the apparatus exceeds the potential by 10 times. (Answer:32.3 MJ ).

7. When is less energy consumed: when launching a satellite along the meridian or along the equator in the direction of the Earth's rotation? (Answer:When launched along the equator in the direction of the Earth's rotation. In this case, the speed of the daily rotation of the earth is added to the speed of the satellite ) .

8. Why does it take more energy to launch a satellite with a larger mass into a given orbit than a satellite with a smaller mass? (Answer:In the same orbit, the satellites have different total mechanical energy ).

9. The Soviet automatic station "Astron" weighing about 35 tons, put into orbit in 1983, circulated above the Earth at altitudes ranging from 2000 km (perigee) to 200,000 km (apogee). Determine the potential energy at these heights and how much did the kinetic energy change when moving to a higher orbit?

10. The Arizona meteorite crater has a diameter of 1207 m, a depth of 174 m, and a height of the surrounding rampart from 40 to 50 m. Considering the mass of the meteoroid (giant meteorite) is 10 6 tons, and the speed is equal to the geocentric velocity (30 km / s). Determine its kinetic energy.

11. What should an astronaut do in order to send any body to Earth from an Earth satellite moving in a circular orbit? ( Answer: An astronaut can achieve this with three ways . 1) Reduce the speed of the body compared to the speed of the ship, i.e., throw the body back. 2) Transfer the body to an orbit of a smaller radius, where, in order to stay in orbit, the body needs a greater horizontal velocity than the ship has, and hence the body. To do this, the body must be thrown down. 3) Combining the first with the second, you can throw the body back and down. The most efficient (energy-saving) method is the first one. ) .

12. Let's imagine that a container with a mass of 95 kg was sent from a space ship-satellite from a height of 550 km above the Earth's surface along a spiral trajectory to the Earth. To do this, its orbital speed was reduced to 6.5 km / s. The container was completely inhibited by the atmosphere. How much heat is released during this braking? ( Answer:2500 MJ ) .

13. The mechanical energy of each kilogram of the substance of a spacecraft launched into a near-Earth orbit at a height of 300 km and having a first cosmic velocity of 8 km/s is equal to 34*10 7 J. This energy is only 5% of the energy expended in delivering each kilogram of the device into orbit. Using these data, determine the amount of fuel consumed during the launch of the Salyut station with a mass of 18,900 kg into such an orbit. (Answer: 2800 t ).

14. An astronaut who is in open space needs to return to the ship. On the ground, this task is simple, you know, keep walking, but in space everything is much more difficult, since there is nothing to push off with your feet. How can an astronaut move? (Answer:it is necessary to throw some object (if it does not turn out to be the position of the astronaut will become tragic) in the direction opposite to the rocket. Then, in accordance with the law of conservation of momentum, a person will acquire a speed directed towards the rocket ).

15. The launch vehicle delivered the satellite into orbit and accelerated it to the desired speed. The mechanism separating the last stage of the rocket from the satellite told it a speed (relative to the common center of gravity) of 1 km / s. What additional speed will the satellite get if its mass is 5 tons, and the mass of the last stage without fuel is 9 tons?

16. If a space rocket ejected its gases not gradually, but all together in one push, then what amount of fuel would be needed to give the first space velocity to a single-stage rocket weighing 1 ton at a gas ejection speed of 2 km / s? (Answer: m4 T ).

17. From a rocket engine in time t the mass of gas flows out evenly m with the speed of expiration u. What is the thrust force of the engine? (Answer: ).

18. From a two-stage ballistic missile with a total mass of 1 t at the moment of reaching a speed of 171 m / s, its second stage with a mass of 0.4 t was separated at a speed of 185 m / s. Determine the speed at which the first stage of the rocket began to move. (Answer:161.7m/s ) .

19. With what minimum speed relative to the spaceship must an iron meteorite move so that it can melt as a result of a collision with a ship? The temperature before the collision with the meteorite is equal to 100 0 C. Assume that the amount of heat released as a result of the collision is distributed equally between the ship and the meteorite. The specific heat capacity of iron is 460 J / (kg * K), the specific heat of fusion of iron is 2.7 * 10 5 J / kg and the melting point of iron is 1535 0 C. (Answer:2 km ) .

THERMAL PHENOMENA

1. Why does the skin of the descent spacecraft heat up?

2. What methods of heat distribution are possible inside a satellite moving in a circular orbit and filled with gas? (Answer:due to weightlessness, there is almost no natural circulation of gas. If there is no forced movement of the gas, then only heat conduction and radiation are possible).

3. Can energy be transferred by convection under weightless conditions, for example, in satellites, when normal atmospheric pressure is maintained on board? Why? (Answer:cannot, because in zero gravity there is no convection ).

4. Why is forced air circulation necessary in satellites and spacecraft? (Answer:it would be impossible to maintain a normal temperature on board the spacecraft, the astronauts would breathe exhaled air, because in a state of weightlessness there is no convection, i.e., natural air circulation ) .

5. Why does the skin of spaceships collapse when they enter the dense layers of the atmosphere when they return to Earth?

6. Why are spaceships and rockets sheathed with metals such as tantalum and tungsten?

7. The mass of the icy core of Halley's comet is 4.97 * 10 11 tons. Assuming that every second it loses 30 tons of water and during its movement around the Sun there are 4 months, calculate how many revolutions the ice composition of the core will last. The orbital period of Halley's comet is 76 years. Determine after how many years its core will completely evaporate. (Answer:The loss of ice per day is 2.6 * 10 6 tons. But intensive evaporation of water from the core occurs only near the Sun, at distances from it no more than 1 AU. With each return to the Sun, Halley's comet moves within this distance for about 4 months. (120 days) and, therefore, loses 3.1 * 10 8 tons over such a time interval. It follows that the icy composition of the nucleus will be enough for another 1600 revolutions of the comet around the Sun. And since the comet's orbital period is 76 years, its icy core will evaporate completely only after 122,000 years. ) .

8. Under normal conditions, when boiling, vapor bubbles rise to the free surface of the liquid. How should boiling proceed in a state of weightlessness, for example, in a satellite, on board of which normal atmospheric pressure is maintained? (Answer:the vapor bubbles, increasing, do not come off, but remain on the bottom and walls of the vessel, since under conditions of weightlessness they are not affected by the Archimedean force ).

9. What will happen if an astronaut, leaving the ship into outer space, opens a vessel with water? (Answer:in an airless space (at low pressure), water will begin to boil and evaporate quickly. The liquid cools and solidifies. The evaporation process will continue, but slowly).

10. In the engines of the launch vehicle of the Vostok spacecraft, kerosene is used as fuel. What mass of kerosene was burned for 1 second of engine operation, if 1.5 * 10 7 kJ of energy was released in this case?

11. The American manned reusable transport spacecraft "Space Shuttle" uses liquid hydrogen as fuel, the mass of fuel in the tank at launch is 102 tons. Calculate the energy that is released when this fuel is burned during the flight. The specific heat of combustion of hydrogen is 120 MJ/kg. (Answer:12,240 GJ. ) .

12. The power of the launch vehicle of the Energia spacecraft is 125 MW. What mass of fuel (kerosene) burns in the engines of the launch vehicle during the first 90 seconds from the flight? The specific heat of combustion of kerosene is 45 MJ/kg. (Answer:250 kg) .

13. On a summer day, 1 m 2 of the earth's surface illuminated by the sun's rays receives up to 1.36 kJ of energy per second. How much heat will a plowed field of 20 hectares receive in 10 minutes? (Answer:272 MJ ) .

14. The power of solar radiation incident on the Earth, 2 * 10 14 kW. How much energy does the Earth receive per day if about 55% of this energy is absorbed by the atmosphere and the earth's surface, and 45% is reflected? How much oil must be burned to obtain the same amount of energy? The specific heat of combustion of oil is 46 MJ/kg. (Answer:9.5 * 10 21 J; 2.1 * 10 8 kt ) .

15. According to the project of B.K. The glass blank from which the mirror was made weighed 700 kN and, after casting at a temperature of 1600 0 C, was cooled for 736 days. Assuming that the final temperature of the casting was 20 0 C, calculate the energy released during glass cooling (the specific heat capacity of glass is 800 J/(kg * 0 C). (Answer:88500 MJ ).

16. A satellite weighing 2.1 tons is moving at a speed of 7.5 km/s. What amount of heat would be released during a collision of a satellite with a cosmic body, if as a result of the collision the satellite would stop relative to the Earth? How much water could be heated due to this energy from 0 to 100 0 C? ( Answer: 5.9 * 10 10 J; 3000 T ) .

(Illustrated cards see Appendix 1)

USED ​​BOOKS

1. B.A. Vorontsov-Velyaminov "Collection of problems in astronomy", Moscow, Prosveshchenie, 1980.
2. A.V. Rotar "Tasks for a young cosmonaut", Moscow, Education, 1965.
3. M.M. Dagaev, V.M. Charugin "Astrophysics", a book for reading on astronomy, Moscow, Education, 1988.