Scientific discoveries that brought us into space: Rockets. How it works: space rockets What does a rocket do in space

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Questions.

1. Based on the law of conservation of momentum, explain why a balloon moves in the opposite direction to the stream of compressed air coming out of it.

2. Give examples of the reactive motion of bodies. In nature, an example is the reactive movement of plants: the ripened fruits of a crazy cucumber; and animals: squid, octopus, jellyfish, cuttlefish, etc. (animals move by throwing out the water they absorb). In technology, the simplest example of jet propulsion is segner wheel , more complex examples

are: the movement of rockets (space, gunpowder, military), water vehicles with a jet engine (hydrocycles, boats, motor ships), air vehicles with a jet engine (jet aircraft).

3. What is the purpose of rockets? Rockets are used in various fields of science and technology: in military affairs, in scientific research

, in astronautics, in sports and entertainment.

4. Using Figure 45, list the main parts of any space rocket.

Spacecraft, instrument compartment, oxidizer tank, fuel tank, pumps, combustion chamber, nozzle.

5. Describe the principle of operation of a rocket. In accordance with the law of conservation of momentum, a rocket flies due to the fact that gases with a certain momentum are pushed out of it at high speed, and the rocket is given an impulse of the same magnitude, but directed in the opposite direction. Gases are emitted through a nozzle in which fuel burns, reaching high temperature

and pressure. The nozzle receives fuel and oxidizer, which are forced there by pumps.

6. What does the speed of a rocket depend on?

The speed of the rocket depends primarily on the speed of gas flow and the mass of the rocket. The rate of gas flow depends on the type of fuel and the type of oxidizer. The mass of the rocket depends, for example, on what speed they want to impart to it or on how far it should fly.

7. What is the advantage of multi-stage rockets over single-stage ones?

Multistage rockets are capable of reaching higher speeds and flying further than single-stage rockets. 8. How to land?

The landing of the spacecraft is carried out in such a way that its speed decreases as it approaches the surface. This is achieved using brake system, which can be played by or parachute system braking or deceleration can be carried out using a rocket engine, with the nozzle directed downwards (towards the Earth, Moon, etc.), due to which the speed is reduced.

Exercises.

1. From a boat moving at a speed of 2 m/s, a person throws an oar with a mass of 5 kg at a horizontal speed of 8 m/s opposite to the movement of the boat. At what speed did the boat begin to move after the throw, if its mass together with the mass of the person is 200 kg?

2. What speed will the rocket model get if the mass of its shell is 300 g, the mass of gunpowder in it is 100 g, and gases escape from the nozzle at a speed of 100 m/s? (Consider the gas outflow from the nozzle to be instantaneous).

3. On what equipment and how is the experiment shown in Figure 47 carried out? What physical phenomenon is being demonstrated in this case, what does it consist of, and what physical law underlies this phenomenon?
Note: the rubber tube was positioned vertically until water began to flow through it.

A funnel with a rubber tube attached to it from below with a curved nozzle at the end was attached to the tripod using a holder, and a tray was placed below. Then they began to pour water from the container from above into the funnel, while the water poured from the tube into the tray, and the tube itself shifted from a vertical position. This experiment illustrates reactive motion based on the law of conservation of momentum.

4. Perform the experiment shown in Figure 47. When the rubber tube deviates from the vertical as much as possible, stop pouring water into the funnel. While the water remaining in the tube flows out, observe how: a) the flight range of the water in the stream (relative to the hole in the glass tube); b) position of the rubber tube. Explain both changes.

a) the flight range of water in the jet will decrease; b) as water flows out, the tube will approach horizontal position. These phenomena are due to the fact that the water pressure in the tube will decrease, and therefore the impulse with which the water is ejected.

And we know that for movement to occur, some force must be applied. The body either itself must push off from something, or an external body must push the given one. This is well known and understandable to us from life experience.

What to push off from in space?

At the surface of the Earth, you can push off from the surface or from objects on it. To move on the surface, they use legs, wheels, tracks, and so on. In water and air, you can push away from the water and air themselves, which have a certain density and therefore allow you to interact with them. Nature has adapted fins and wings for this purpose.

Man has created engines based on propellers, which greatly increase the area of ​​contact with the environment due to rotation and allow them to push off water and air. But what about the case of airless space? What to start from in space? There is no air there, there is nothing there. How to fly in space? This is where the law of conservation of momentum and the principle of reactive propulsion come to the rescue. Let's take a closer look.

Impulse and the principle of jet propulsion

Momentum is the product of a body's mass and its speed. When a body is stationary, its speed is zero. However, the body has some mass. In the absence of external influences, if part of the mass is separated from the body at a certain speed, then, according to the law of conservation of momentum, the rest of the body must also acquire a certain speed so that the total momentum remains equal to zero.

Moreover, the speed of the remaining main part of the body will depend on the speed with which the smaller part separates. The higher this speed is, the higher the speed of the main body will be. This is understandable if we recall the behavior of bodies on ice or in water.

If two people are nearby, and then one of them pushes the other, then he will not only give him acceleration, but will also fly back. And the harder he pushes someone, the faster he will fly away.

Surely you have been to similar situation, and you can imagine how this happens. So, this is what jet propulsion is based on.

Rockets that implement this principle eject some of their mass at high speed, as a result of which they themselves acquire some acceleration in the opposite direction.

Streams of hot gases resulting from fuel combustion are ejected through narrow nozzles to give them maximum speed. At the same time, the mass of the rocket decreases by the amount of the mass of these gases, and it acquires a certain speed. This is how the principle of reactive motion in physics is realized.

Rocket flight principle

Rockets use a multi-stage system. During flight, the lower stage, having used up its entire fuel supply, is separated from the rocket to reduce its overall mass and facilitate flight.

The number of stages is reduced until the working part remains in the form of a satellite or other spacecraft. The fuel is calculated in such a way that it is enough to enter orbit.

A Brief History of Rockets

The general principle of jet flight, which formed the basis of all rockets, is simple - some part is separated from the body, setting everything else in motion.

It is unknown who was the first to implement this principle, but various guesses and conjectures bring the genealogy of rocket science right back to Archimedes. What is known for certain about the first such inventions is that they were actively used by the Chinese, who loaded them with gunpowder and launched them into the sky due to the explosion. Thus they created the first solid fuel rockets. European governments showed great interest in missiles early

Second rocket boom

Rockets waited in the wings and waited: in the 1920s, the second rocket boom began, and it is associated primarily with two names.

Konstantin Eduardovich Tsiolkovsky - a self-taught scientist from Ryazan province, despite the difficulties and obstacles, he himself reached many discoveries, without which it would have been impossible to even talk about space. Idea of ​​use liquid fuel, Tsiolkovsky’s formula, which calculates the speed required for flight based on the ratio of the final and initial masses, a multi-stage rocket - all this is his merit. Largely under the influence of his works, domestic rocket science was created and formalized. In the Soviet Union, societies and circles for the study of jet propulsion began to spontaneously arise, including GIRD - a group for the study of jet propulsion, and in 1933, under the patronage of the authorities, the Jet Institute appeared.

Konstantin Eduardovich Tsiolkovsky.
Source: Wikimedia.org

The second hero of the rocket race is the German physicist Wernher von Braun. Brown had an excellent education and a lively mind, and after meeting another luminary of world rocket science, Heinrich Oberth, he decided to put all his efforts into creating and improving rockets. During World War II, von Braun actually became the father of the Reich's “weapon of retaliation” - the V-2 rocket, which the Germans began using on the battlefield in 1944. “Winged Horror,” as it was called in the press, brought destruction to many English cities, but, fortunately, at that time the collapse of Nazism was already a matter of time. Wernher von Braun, together with his brother, decided to surrender to the Americans, and, as history has shown, this was a lucky ticket not only and not so much for scientists, but for the Americans themselves. Since 1955, Brown has worked for the American government, and his inventions form the basis space program USA.

But let's go back to the 1930s. The Soviet government appreciated the zeal of enthusiasts on the path to space and decided to use it in its own interests. During the war years, the “Katyusha” showed itself to be excellent - a multiple launch rocket system that fired rockets. It was in many ways an innovative weapon: the Katyusha, based on a Studebaker light truck, arrived, turned around, fired at the sector and left, not allowing the Germans to come to their senses.

The end of the war presented our leadership with a new task: the Americans showed the world all their power nuclear bomb, and it became quite obvious that only those who have something similar can claim superpower status. But there was a problem. The fact is that, in addition to the bomb itself, we needed delivery vehicles that could bypass US air defense. Airplanes were not suitable for this. And the USSR decided to rely on missiles.

Konstantin Eduardovich Tsiolkovsky died in 1935, but he was replaced by a whole generation of young scientists who sent man into space. Among these scientists was Sergei Pavlovich Korolev, who was destined to become the Soviets' "trump card" in the space race.

The USSR began to create its own intercontinental missile with all zeal: institutes were organized, the best scientists were gathered, a research institute for missile weapons, and work is in full swing.

Only a colossal effort of effort, resources and minds made it possible Soviet Union V as soon as possible build your own rocket, which they called R-7. It was its modifications that launched Sputnik and Yuri Gagarin into space, and it was Sergei Korolev and his associates who launched the space age of mankind. But what does a space rocket consist of?