Reactive motion in nature and technology. Presentation on "Reactive propulsion in nature" Reactive propulsion in nature briefly

Reactive motion in nature and technology

ABSTRACT IN PHYSICS

Jet propulsion- the movement that occurs when some part of the body is separated from the body at a certain speed.

Reactive force occurs without any interaction with external bodies.

The use of jet propulsion in nature

Many of us in our lives have met while swimming in the sea with jellyfish. In any case, there are quite enough of them in the Black Sea. But few people thought that jellyfish use jet propulsion for movement. In addition, this is how dragonfly larvae and some species of marine plankton move. And often the efficiency of marine invertebrates using jet propulsion is much higher than that of technological inventions.

Jet propulsion is used by many molluscs - octopuses, squid, cuttlefish. For example, a scallop mollusk moves forward due to the reactive force of a stream of water ejected from the shell when its valves are sharply compressed.

Octopus

Cuttlefish

Cuttlefish, like most cephalopods, moves in water in the following way. It draws water into the gill cavity through the lateral slit and a special funnel in front of the body, and then vigorously throws out a stream of water through the funnel. The cuttlefish directs the funnel tube to the side or back and rapidly squeezing water out of it, can move in different directions.

Salpa is a sea animal with a transparent body, when it moves, it receives water through the front opening, and water enters a wide cavity, inside which the gills are stretched diagonally. As soon as the animal takes a long sip of water, the hole is closed. Then the longitudinal and transverse muscles of the salpa contract, the whole body contracts, and water is pushed out through the posterior opening. The reaction of the flowing jet pushes the salpa forward.

Of greatest interest is the squid jet engine. The squid is the largest invertebrate inhabitant of the ocean depths. Squids have reached the highest perfection in jet navigation. In them, even the body with its external forms copies the rocket (or, better to say, the rocket copies the squid, since it has an indisputable priority in this matter). When moving slowly, the squid uses a large diamond-shaped fin that bends periodically. He uses a jet engine for a quick throw. Muscle tissue - the mantle surrounds the body of the mollusk from all sides, the volume of its cavity is almost half the volume of the body of the squid. The animal sucks in water inside the mantle cavity, and then abruptly throws out a stream of water through a narrow nozzle and at high speed moves backward in jerks. In this case, all ten tentacles of the squid gather in a knot above the head, and it acquires a streamlined shape. The nozzle is equipped with a special valve, and the muscles can turn it, changing the direction of movement. The squid engine is very economical, it is capable of speeds up to 60 - 70 km / h. (Some researchers believe that even up to 150 km / h!) No wonder the squid is called a “live torpedo”. Bending the tentacles folded in a bundle to the right, left, up or down, the squid turns in one direction or the other. Since such a rudder is very large in comparison with the animal itself, its slight movement is enough for the squid, even at full speed, to easily dodge a collision with an obstacle. A sharp turn of the steering wheel - and the swimmer rushes in the opposite direction. So he bent the end of the funnel back and now slides head first. He bent it to the right - and a jet push threw it to the left. But when you need to swim fast, the funnel always sticks out right between the tentacles, and the squid rushes forward with its tail, as a crayfish would run - a runner endowed with the agility of a horse.

If there is no need to rush, squid and cuttlefish swim, undulating with fins - miniature waves run along them from front to back, and the animal glides gracefully, occasionally pushing itself also with a stream of water thrown out from under the mantle. Then the individual shocks that the mollusk receives at the time of the eruption of water jets are clearly visible. Some cephalopods can reach speeds of up to fifty-five kilometers per hour. It seems that no one has made direct measurements, but this can be judged by the speed and range of flying squid. And such, it turns out, there are talents in the relatives of the octopus! The best mollusk pilot is the stenoteutis squid. English sailors call it - flying squid ("flying squid"). It is a small herring-sized animal. He pursues fish with such impetuosity that he often jumps out of the water, sweeping like an arrow over its surface. He resorts to this trick and saving his life from predators - tuna and mackerel. Having developed the maximum jet thrust in the water, the pilot squid takes off into the air and flies over the waves for more than fifty meters. The apogee of a live rocket's flight lies so high above the water that flying squids often land on the decks of ocean-going ships. Four to five meters is not a record height to which squid rise into the sky. Sometimes they fly even higher.

The English shellfish researcher Dr. Rees described in a scientific article a squid (only 16 centimeters long), which, having flown a fair distance through the air, fell on the yacht's bridge, which was almost seven meters above the water.

It happens that many flying squids descend on the ship in a sparkling cascade. The ancient writer Trebius Niger once told a sad story about a ship that even sank under the weight of flying squids that fell on its deck. Squids can take off without acceleration.

Octopuses can fly too. French naturalist Jean Verany saw an ordinary octopus speed up in an aquarium and suddenly jumped out of the water backwards. After describing an arc five meters long in the air, he plopped back into the aquarium. Gathering speed to jump, the octopus moved not only due to jet thrust, but also rowed with tentacles.
Baggy octopuses swim, of course, worse than squids, but at critical moments they can show a record class for the best sprinters. Staff at the California Aquarium tried to photograph an octopus attacking a crab. The octopus rushed to its prey so quickly that there was always grease on the film, even when shooting at the highest speeds. So the throw lasted hundredths of a second! Usually, octopuses swim relatively slowly. Joseph Seinle, who studied the migration of octopuses, calculated that an octopus, half a meter in size, floats on the sea at an average speed of about fifteen kilometers per hour. Each stream of water thrown out of the funnel pushes it forward (or rather, backward, since the octopus swims backwards) two to two and a half meters.

Jet propulsion can also be found in the plant world. For example, ripe fruits of "mad cucumber" at the slightest touch bounce off the stalk, and a sticky liquid with seeds is thrown out of the hole with force. At the same time, the cucumber itself flies in the opposite direction up to 12 m.

Knowing the law of conservation of momentum, you can change your own speed of movement in open space. If you are in a boat and have several heavy stones, then by throwing stones in a certain direction, you will move in the opposite direction. The same will happen in outer space, but there they use jet engines for this.

Everyone knows that a shot from a gun is accompanied by a recoil. If the weight of the bullet were equal to the weight of the gun, they would fly at the same speed. Recoil occurs because the rejected mass of gases creates a reactive force, thanks to which movement can be ensured both in air and in airless space. And the greater the mass and velocity of the outflowing gases, the greater the recoil force our shoulder feels, the stronger the reaction of the gun, the greater the reactive force.

The use of jet propulsion in technology

For many centuries, humanity has dreamed of space travel. Science fiction writers have offered a variety of means to achieve this goal. In the 17th century, the story of the French writer Cyrano de Bergerac about the flight to the moon appeared. The hero of this story reached the moon in an iron cart, over which he was constantly throwing a strong magnet. Pulling towards him, the wagon rose higher and higher above the Earth until it reached the moon. And Baron Munchausen said that he climbed to the moon on a bean stalk.

At the end of the first millennium AD, China invented jet propulsion, which propelled rockets - bamboo tubes filled with gunpowder, they were also used as fun. One of the first projects of cars was also with a jet engine and this project belonged to Newton.

The author of the world's first project of a jet aircraft designed for human flight was the Russian revolutionary N.I. Kibalchich. He was executed on April 3, 1881 for participating in the assassination attempt on Emperor Alexander II. He developed his project in prison after the death sentence. Kibalchich wrote: “While in prison, a few days before my death, I am writing this project. I believe in the feasibility of my idea, and this belief supports me in my terrible position ... I will calmly face death, knowing that my idea will not perish with me. "

The idea of using rockets for space flights was proposed at the beginning of this century by the Russian scientist Konstantin Eduardovich Tsiolkovsky. In 1903, an article by the teacher of the Kaluga gymnasium K.E. Tsiolkovsky "Exploration of world spaces by jet devices". This work contained the most important mathematical equation for astronautics, now known as the "Tsiolkovsky formula", which described the motion of a body of variable mass. In the future, he developed a scheme for a rocket engine on liquid fuel, proposed a multistage rocket design, and expressed the idea of the possibility of creating entire space cities in near-earth orbit. He showed that the only device capable of overcoming the force of gravity is a rocket, i.e. apparatus with a jet engine using fuel and an oxidizer located on the apparatus itself.

Jet engine Is an engine that converts the chemical energy of the fuel into the kinetic energy of a gas jet, while the engine acquires speed in the opposite direction.

The idea of K.E. Tsiolkovsky was implemented by Soviet scientists under the leadership of Academician Sergei Pavlovich Korolev. The first ever artificial Earth satellite using a rocket was launched in the Soviet Union on October 4, 1957.

The principle of jet propulsion is widely used in aviation and astronautics. In outer space, there is no medium with which the body could interact and thereby change the direction and modulus of its velocity, therefore, for space flights, only jet aircraft, i.e. rockets, can be used.

Rocket device

The motion of the rocket is based on the law of conservation of momentum. If at some point in time any body is thrown away from the rocket, then it will acquire the same impulse, but directed in the opposite direction

In any rocket, regardless of its design, there is always a shell and fuel with an oxidizer. The rocket shell includes a payload (in this case, a spacecraft), an instrument compartment, and an engine (combustion chamber, pumps, etc.).

The bulk of the rocket is fuel with an oxidizer (an oxidizer is needed to maintain fuel combustion, since there is no oxygen in space).

Fuel and oxidizer are pumped into the combustion chamber. Fuel, burning, turns into gas of high temperature and high pressure. Due to the large pressure difference in the combustion chamber and in outer space, gases from the combustion chamber rush outward in a powerful jet through a specially shaped bell, called a nozzle. The purpose of the nozzle is to increase the speed of the jet.

Before the launch of the rocket, its impulse is zero. As a result of the interaction of the gas in the combustion chamber and all other parts of the rocket, the gas escaping through the nozzle receives a certain impulse. Then the rocket is a closed system, and its total impulse should be equal to zero even after launch. Therefore, the shell of the rocket completely, which is in it, receives an impulse equal in magnitude to the momentum of the gas, but opposite in direction.

The most massive part of the rocket, designed to launch and accelerate the entire rocket, is called the first stage. When the first massive stage of a multistage rocket runs out of fuel during acceleration, it is separated. Further acceleration is continued by the second, less massive stage, and to the speed previously achieved with the first stage, it adds some more speed, and then separates. The third stage continues to increase the speed to the required value and delivers the payload to orbit.

The first person to fly in outer space was a citizen of the Soviet Union, Yuri Alekseevich Gagarin. April 12, 1961 He circled the globe aboard the Vostok satellite

Soviet rockets were the first to reach the Moon, circled the Moon and photographed its invisible side from Earth, the first to reach the planet Venus and deliver scientific instruments to its surface. In 1986, two Soviet spacecraft "Vega-1" and "Vega-2" examined Halley's comet at close range, approaching the Sun once every 76 years.

Systems. Technics physical exercise. Target result movement does not depend on ... nature Healing forces nature have a significant impact ... by a combination of inertial forces, reactive and concentrated muscle contractions ...

Multi-ton spaceships soar into the sky, and transparent, gelatinous jellyfish, cuttlefish and octopuses deftly maneuver in the sea waters - what do they have in common? It turns out that in both cases, the principle of jet propulsion is used to move. It is this topic that our today's article is devoted to.

Let's look at history

The most the first reliable information about missiles dates back to the 13th century. They were used by the Hindus, Chinese, Arabs and Europeans in combat as combat and signal weapons. This was followed by centuries of almost complete oblivion of these devices.

In Russia, the idea of using a jet engine was revived thanks to the works of the revolutionary Nikolai Kibalchich. Sitting in the tsarist dungeons, he developed a Russian project for a jet engine and an aircraft for humans. Kibalchich was executed, and his project was gathering dust in the archives of the tsarist secret police for many years.

The basic ideas, drawings and calculations of this talented and courageous man were further developed in the works of K.E. Tsiolkovsky, who proposed using them for interplanetary communications. From 1903 to 1914, he published a number of works, where he convincingly proves the possibility of using jet propulsion for space exploration and substantiates the advisability of using multistage rockets.

Many scientific developments of Tsiolkovsky are still used in rocketry.

Biological rockets

How, in general, did it arise the idea of moving, starting from your own jet stream? Perhaps, by closely observing the marine life, the inhabitants of the coastal zones noticed how this happens in the animal kingdom.

For instance, scallop moves due to the reactive force of the water jet ejected from the shell during the rapid compression of its valves. But he will never keep up with the fastest swimmers - squid.

Their rocket-like bodies rush with their tail forward, ejecting stored water from a special funnel. move according to the same principle, squeezing out water by contracting their transparent dome.

Nature has endowed with a "jet engine" and a plant called "squirting cucumber". When its fruits are fully ripe, in response to the slightest touch, it shoots out the gluten with the seeds. The fetus itself is thrown in the opposite direction at a distance of up to 12 m!

Neither marine life nor plants know the physical laws underlying this mode of movement. We will try to figure it out.

Physical foundations of the principle of jet propulsion

Let's turn to the simplest experiment first. Inflate a rubber ball and, without tying, let us go into free flight. The rapid movement of the ball will continue as long as the stream of air emanating from it is strong enough.

To explain the results of this experiment, we must turn to Law III, which states that two bodies interact with forces equal in magnitude and opposite in direction. Consequently, the force with which the ball acts on the jets of air escaping from it is equal to the force with which the air pushes the ball away from itself.

Let's transfer this reasoning to the rocket. These devices throw out some of their mass at great speed, as a result of which they themselves receive acceleration in the opposite direction.

From the point of view of physics, this the process is clearly explained by the law of conservation of momentum. Momentum is the product of body mass by its velocity (mv) While the rocket is at rest, its velocity and momentum are equal to zero. If a jet stream is thrown out of it, then the remaining part, according to the law of conservation of momentum, must acquire such a speed that the total momentum is still equal to zero.

Let's turn to the formulas:

m g v g + m p v p = 0;

m g v g = - m p v p,

where m g v g impulse created by a jet of gases, m p v p impulse received by the rocket.

The minus sign shows that the direction of movement of the rocket and the jet is opposite.

The structure and principle of operation of a jet engine

In technology, jet engines set in motion airplanes, rockets, and launch spacecraft into orbits. Depending on the purpose, they have a different device. But each of them has a supply of fuel, a chamber for its combustion and a nozzle that accelerates the jet stream.

The interplanetary automatic stations are also equipped with an instrument compartment and cabins with a life support system for astronauts.

Modern space rockets are complex, multistage aircraft that use the latest advances in engineering. After the launch, the fuel in the lower stage first burns, after which it is separated from the rocket, reducing its total mass and increasing its speed.

Then fuel is consumed in the second stage, and so on. Finally, the aircraft is brought to a predetermined trajectory and begins its independent flight.

Let's dream a little

The great dreamer and scientist K.E. Tsiolkovsky gave future generations the confidence that jet engines would allow mankind to break out of the earth's atmosphere and rush into space. His prediction came true. The moon, and even distant comets, are successfully explored by spacecraft.

In astronautics, liquid jet engines are used. Using petroleum products as fuel, but the speeds that can be obtained with their help are insufficient for very long flights.

Perhaps you, our dear readers, will witness the flights of earthlings to other galaxies on vehicles with nuclear, thermonuclear or ion jet engines.

If this message is useful to you, it's good to see you.

Nomination "The World Around"

In preparation for the New Years celebration, I decorated the apartment with balloons. When I inflated the balloons, one of them escaped from my hands and flew away from me at high speed in the opposite direction. I asked myself the question: what happened to the balloon? The parents explained that this is jet propulsion. Does the balloon fly like a rocket?

Hypothesis, which I put forward in the course of research: perhaps jet propulsion occurs in nature and in everyday life.

Goals work:

study the physical principles of jet propulsion
identify where jet propulsion occurs in nature and in everyday life.

To confirm or deny my hypothesis, I set myself tasks:

conduct experiments illustrating jet propulsion,
read popular science literature about jet propulsion,
find relevant materials on the Internet,
create a presentation on this topic.

HISTORY REFERENCE

Jet propulsion was used even in the manufacture of the first powder fireworks and signal rockets in China in the X century. At the end of the 18th century, Indian troops in the fight against the British colonialists used black powder rockets. In Russia, powder rockets were adopted at the beginning of the 19th century.

During World War II, German troops used V-2 ballistic missiles, shelling British and Belgian cities. Soviet troops used Katyusha multiple rocket launchers with great success.

The progenitors of jet engines:

Greek mathematician and mechanic Heron of Alexandria (Appendix 2.1), creator of eolipilus (Geron ball);
the Hungarian scientist Janos Segner (Appendix 2.3), who created the "Segner wheel";
NI Kibalchich was the first to use jet propulsion for space flights;
Further theoretical development of rocket navigation belongs to the Russian scientist Tsiolkovsky K.E.
His works inspired S.P. Korolev to create aircraft for manned space flight. Thanks to his ideas, for the first time in the world, an artificial Earth satellite was launched (04.10.57) and the first manned satellite with a pilot-cosmonaut on board Yu.A. Gagarin (April 12, 1961).

PHYSICAL PRINCIPLES REACTIVE MOTION AND ROCKET DEVICE

Reactive motion is based on the principle of action and reaction: if one body acts on another, then exactly the same force will act on it, but directed in the opposite direction.

I have conducted an experiment that proves that every action has an equal opposition. (video clip)

A modern space rocket is a very complex and heavy aircraft, consisting of hundreds of thousands and millions of parts. It consists of working fluid(i.e. incandescent gases formed as a result of fuel combustion and emitted in the form of a jet stream) and the final "dry" the mass of the rocket remaining after the ejection of incandescent gases from the rocket (this is the shell of the rocket, that is, the life support systems of astronauts, equipment, etc.). To achieve cosmic speeds, multistage rockets are used. When a jet gas jet is ejected from the rocket, the rocket itself rushes in the opposite direction, accelerating to the 1st cosmic speed: 8 km / s.

I carried out an experiment on the interaction of carts and proved that the greater the mass of the fuel, the greater the speed of the rocket. This means that space flights require a huge amount of fuel.

REACTIVE MOTION IN NATURE

So, where does jet propulsion occur in nature? Fish swim, birds fly, animals run. Everything seems to be simple. No matter how it is. The hunt for wandering in animals is not a whim, but a harsh necessity. If you want to eat, be able to move. If you don't want to be eaten, be able to sneak away. To move quickly in space, you need to develop high speeds.

For this, for example, scallop- got a jet engine. It vigorously throws water out of the shell and flies a distance that is 10-20 times its own length! Salpa, dragonfly larvae, fishes- they all use the principle of jet propulsion to move in space. Octopus develops a speed of up to 50 km / h and this is due to jet thrust. He can even walk on land, because he has a supply of water in his bosom for this case. Squid- the largest invertebrate inhabitant of the ocean depths moves according to the principle of jet propulsion.

Examples of jet propulsion can also be found in the plant world. In southern countries (and on our Black Sea coast too) a plant grows called "squirting cucumber". One has only to lightly touch the ripe fruit, similar to a cucumber, as it bounces off the stalk, and through the hole formed from the fruit, a liquid with seeds flies out at a speed of up to 10 m / s. The cucumbers themselves fly off in the opposite direction. cucumber (otherwise it is called "ladies' pistol") by more than 12 m.

In everyday life by example soul on flexible hose you can see the manifestation of jet propulsion. One has only to put water into the shower, as the handle with a spray at the end will deviate in the direction opposite to the flowing jets.

The principle of jet propulsion is the basis for the operation of sprinklers (Appendix 7.2) for irrigating plantings in orchards and vegetable gardens. The water pressure rotates the head with water sprayers.

The principle of jet propulsion helps propulsion swimmer... The more the swimmer pushes the water back, the faster he swims. (Appendix 7.3)

Engineers have already created an engine similar to that of a squid. It is called a water cannon. (Appendix 7.4)

CONCLUSION

In the course of work:

1. I found out that the principle of jet propulsion is the physical law of action and reaction

2. Experimentally confirmed the dependence of the speed of movement of a body on the mass of another body acting on it.

3. I was convinced that jet propulsion is found in technology, everyday life and nature, and even cartoons.

4. Now that I know about jet propulsion, I can avoid many troubles, for example, jumping from a boat to the shore, firing a gun, including showers, etc.

So I can argue that hypothesis, the one put forward by me was confirmed: the principle of jet propulsion is very common in nature and in everyday life.

LITERATURE

A book for reading on physics, grade 6-7, I.G. Kirillova, - M: Education, 1978. -97-99s
Physics - for young people for extracurricular reading grade 7. M.N. Alekseeva, -M: Education, 1980.- 113 s
Hello, physics. L.Ya. Galperstein, -M: Children's literature, 1967.
Encyclopedia of Science, A. Craig, K. Rosny, -M: Rosman, 1997.- 29 p.
Hello octopus. "Misha" magazine, 1995, No. 8, 12-13s
Legs, wings and even ... a jet engine. "Misha" magazine, 1995, No. 8, 14с
Wikipedia: -ru.wikipedia.org

For many people, the very concept of "jet propulsion" is strongly associated with modern achievements of science and technology, especially physics, and images of jet planes or even spaceships flying at supersonic speeds using the notorious jet engines appear in their heads. In fact, the phenomenon of jet propulsion is much more ancient than even man himself, because it appeared long before us humans. Yes, jet propulsion is actively represented in nature: jellyfish and cuttlefish have been swimming in the depths of the sea for millions of years according to the same principle by which modern supersonic jet aircraft fly today.

History of jet propulsion

Since ancient times, various scientists have observed the phenomena of jet propulsion in nature, so the ancient Greek mathematician and mechanic Heron wrote about him earlier than anyone else, however, he never went beyond theory.

If we talk about the practical application of jet propulsion, the first here were the inventive Chinese. Around the 13th century, they guessed to borrow the principle of movement of octopuses and cuttlefish when inventing the first missiles, which they began to use, both for fireworks and for military operations (as a combat and signal weapon). A little later, this useful invention of the Chinese was adopted by the Arabs, and from them already by the Europeans.

Of course, the first conditionally rocket missiles had a relatively primitive design and for several centuries they practically did not develop in any way, it seemed that the history of the development of jet propulsion had come to a standstill. A breakthrough in this matter occurred only in the 19th century.

Who Discovered Jet Propulsion?

Perhaps, the laurels of the discoverer of jet propulsion in the "new time" can be awarded to Nikolai Kibalchich, not only a talented Russian inventor, but also a revolutionary Narodnaya Volya. He created his project of a jet engine and an aircraft for people while sitting in a tsarist prison. Later, Kibalchich was executed for his revolutionary activities, and his project remained gathering dust on the shelves in the archives of the tsarist secret police.

Later, Kibalchich's works in this direction were discovered and supplemented by the works of another talented scientist K.E. Tsiolkovsky. From 1903 to 1914, he published a number of works in which he convincingly proved the possibility of using jet propulsion in the creation of spaceships for the study of outer space. He also formed the principle of using multistage rockets. To this day, many of Tsiolkovsky's ideas are used in rocketry.

Examples of jet propulsion in nature

Surely while swimming in the sea, you saw jellyfish, but you hardly thought that these amazing (and, moreover, slow) creatures move precisely with the help of jet propulsion. Namely, by shrinking their transparent dome, they squeeze out water, which serves as a kind of "jet engine" for jellyfish.

The cuttlefish also has a similar mechanism of movement - through a special funnel in front of the body and through the lateral slit, it draws water into its gill cavity, and then vigorously throws it out through the funnel, directed backward or sideways (depending on the direction of movement of the desired cuttlefish).

But the most interesting jet engine created by nature is found in squid, which can quite rightly be called "living torpedoes". Indeed, even the body of these animals resembles a rocket in its shape, although in truth everything is exactly the opposite - it is a rocket with its design that copies the body of a squid.

If the squid needs to make a quick throw, it uses its natural jet engine. Its body is surrounded by a mantle, a special muscle tissue, and half of the volume of the entire squid falls on the mantle cavity into which it sucks water. Then he abruptly throws out the collected stream of water through a narrow nozzle, while folding all his ten tentacles over his head in such a way as to acquire a streamlined shape. Thanks to such advanced jet navigation, squid can reach impressive speeds of 60-70 km per hour.

Among the owners of a jet engine in nature there are plants, namely the so-called "mad cucumber". When its fruits ripen, in response to the lightest touch, it shoots out gluten with seeds

Jet propulsion law

Squids, "mad cucumbers", jellyfish and other cuttlefish have been using jet propulsion since ancient times, without thinking about its physical essence, but we will try to figure out what is the essence of jet propulsion, what kind of movement is called reactive, and give it a definition.

To begin with, you can resort to a simple experiment - if you inflate an ordinary balloon with air and, without tying it, let it fly, it will fly rapidly until it runs out of air. This phenomenon is explained by Newton's third law, which says that two bodies interact with forces equal in magnitude and opposite in direction.

That is, the force of the impact of the ball on the air flows escaping from it is equal to the force with which the air pushes the ball away from itself. A rocket works in a way similar to a ball, which at high speed throws out part of its mass, while receiving a strong acceleration in the opposite direction.

The law of conservation of momentum and jet propulsion

Physics explains the process of jet propulsion. Impulse is the product of body mass by its velocity (mv). When a rocket is at rest, its momentum and velocity are zero. When a jet stream starts to be ejected from it, then the rest, according to the law of conservation of momentum, should acquire such a speed at which the total momentum will still be equal to zero.

Jet Propulsion Formula

In general, jet propulsion can be described by the following formula:
m s v s + m p v p = 0
m s v s = -m p v p

where m s v s is the impulse created by the gas jet, m p v p is the impulse received by the rocket.

The minus sign shows that the direction of movement of the rocket and the force of the jet motion of the jet are opposite.

Jet propulsion in technology - the principle of operation of a jet engine

In modern technology, jet propulsion plays a very important role, as jet engines propel airplanes and spaceships. The actual design of a jet engine may differ depending on its size and purpose. But one way or another, each of them has

fuel supply,
chamber for fuel combustion,
nozzle, the task of which is to accelerate the jet stream.

This is what a jet engine looks like.