Presentations on the topic of body impulse conservation of momentum. Body impulse. The law of conservation of momentum - presentation. Resolving problems for impact

René Descartes (), French philosopher, mathematician, physicist and physiologist. Expressed the law of conservation of momentum, defined the concept of impulse of force.

The law of conservation of momentumThe momentum of a body (amount of motion) is a measure of mechanical motion classical theory the product of body weight by its speed. The momentum of a body is a vector quantity, directed in the same way as its velocity. The law of conservation of momentum serves as the basis for explaining a wide range of natural phenomena and is used in various sciences.

Elastic impact Absolutely elastic impact - collisions of bodies, as a result of which their internal energies remain unchanged. With an absolutely elastic impact, not only the momentum is conserved, but also the mechanical energy of the system of bodies. Examples: collision of billiard balls, atomic nuclei and elementary particles. The figure shows an absolutely elastic central impact: As a result of the central elastic impact of two balls of the same mass, they exchange velocities: the first ball stops, the second starts moving at a speed equal to the speed of the first ball.

Inelastic shock Absolutely inelastic shock: this is the name of the collision of two bodies, as a result of which they join together and move on as one whole. In the case of an inelastic impact, a part of the mechanical energy of the interacting bodies is transferred into the internal one, the momentum of the system of bodies is conserved. Examples of inelastic interactions: collision of sticking plasticine balls, car couplers, etc. The figure shows an absolutely inelastic impact: After an inelastic collision, two balls move as a whole at a speed less than the speed of the first ball before the collision.

Calculations: A B C As a result of the experiment, we got: m pistol = 0.154 kg m projectile = 0.04 kg AC = L pistol = 0.1 m L projectile = 1.2 m Using a meter, we determined the movement time of the projectile and the pistol , it was: t pistol = 0.6 s t projectile = 1.4 s Now we determine the speed of the projectile and the pistol during the shot using the formula: V = L / t We got that V of the pistol = 0.1: 0.6 = 0 , 16 m / s V projectile = 1.2: 1.4 = 0.86 m / s And finally we can calculate the momentum of these two bodies by the formula: P = mV We got: P pistol = 0.154 * 0.16 = 0.025 kg * m / s P of the projectile = 0.04 * 0.86 = 0.034 kg * m / s m p * V p = m s * V s 0.025 = 0.034 the disagreement was due to the effect of the friction force on the projectile and the error of the instruments. 0.1 m 1.2 m projectile pistol

Examples of application of the law of conservation of momentum The law is strictly observed in the phenomena of recoil during a shot, the phenomenon of jet propulsion, explosive phenomena and the phenomena of collision of bodies. The law of conservation of momentum is used: when calculating the velocities of bodies during explosions and collisions; when calculating jet vehicles; in the military industry in the design of weapons; in technology - when driving piles, forging metals, etc.

The impulse conservation law underlies jet propulsion. Much credit for the development of the theory of jet propulsion belongs to Konstantin Eduardovich Tsiolkovsky. The founder of the theory of space flight is the outstanding Russian scientist Tsiolkovsky (). He gave the general foundations of the theory of jet propulsion, developed the basic principles and schemes of jet aircraft, and proved the need to use a multistage rocket for interplanetary flights. Tsiolkovsky's ideas were successfully implemented in the USSR in the construction of artificial earth satellites and spacecraft.

Reactive motion The motion of a body resulting from the separation of a part of its mass from it at a certain speed is called reactive. All types of motion, except for jet motion, are impossible without the presence of forces external to a given system, that is, without the interaction of the bodies of this system with the environment, and for the implementation of jet motion, the interaction of the body with the environment is not required. Initially, the system is at rest, i.e., its total momentum is zero. When a part of its mass begins to be ejected from the system at a certain speed, then (since the total momentum of a closed system, according to the law of conservation of momentum, must remain unchanged), the system receives a speed directed in the opposite direction.

Conclusions: During interaction, the change in the momentum of a body is equal to the impulse of the force acting on this body. When bodies interact with each other, the change in the sum of their impulses is equal to zero. And if the change in some quantity is equal to zero, then this means that this quantity is preserved. Practical and experimental verification of the law was successful and once again it was found that the vector sum of the impulses of the bodies that make up a closed system does not change.

"Mechanical movement of bodies" - When? Periodic movement. Mechanical movement. Periodic movement - movement that repeats at regular intervals. Kinematics of periodic motion. Answer. Uniform circular motion. The body was located). Question number 1. Kinematics. Types of mechanical movement.

"Space speed" - The trajectory of bodies moving at low speed. The movement of bodies with the first cosmic speed. Passed by large planets. The first manned flight into space. The circulation period is 96 minutes. The first artificial Earth satellite was launched on October 4, 1957 Mass 83.60 kg. April 12, 1961 V1. Onboard Voyager 2 is a disc with scientific information.

"Body inertia" - Experiment 4. Carts of different masses Why does the speed change in different ways? Airplane launch from the deck of the ship. Body speed cannot change by itself! Inertia of tel. Restrictions on inertial motion - friction, medium resistance. Inertia. Inertia is "laziness". Experience 2. "Coin". From history ... Catapult.

“Rectilinear uniformly accelerated motion” - 10. a. 4. Lesson topic: Rectilinear uniformly accelerated motion. Moving. 1. Speed. Equally accelerated motion ... .for any equal ... 2. How can you determine the speed with a uniform rectilinear motion? The speed and acceleration are the same direction. eight.

"Body impulse" - Let's multiply the right and left sides of the equality by the interaction time. Let's transform this expression. Impulse of power. Examples of jet propulsion can also be found in the plant world. To demonstrate the law of conservation of momentum of a body, let us consider experiment. Consider jet propulsion using the law of conservation of momentum.

"Support and movement" - The skeleton is the support of the body. Sleep on a hard bed with a low pillow. 1 brain 2 Heart 3 Tongue 4 Ears. Correctly sit at the table, desk, chair, do not hunch over. Consult and provide first aid to the patient. The back is straight. You are the doctors of the first medical care... Correct walking posture. What causes bad posture?

There are 10 presentations in total

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Lesson objectives:

Derive and formulate the law of conservation of momentum; Consider examples of applying the law of conservation of momentum; Consider the application of the law of conservation of momentum in solving problems.

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Know:

The formulation of the law of conservation of momentum; Mathematical expression of the law of conservation of momentum; Application of the law of conservation of momentum. Be able to: Derive the law of conservation of momentum; Formulate the law of conservation of momentum; Apply the law of conservation of momentum when solving problems.

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WARM UP

What is body impulse? Write down the mathematical expression for the momentum of the body. In what units is body impulse measured?

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Impulse is a vector physical quantity equal to the product of the body's mass by its velocity. (kg m / s)

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What do we call an impulse of power? Write down the mathematical expression for the impulse of force. In what units is the impulse of force measured?

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The impulse of force is called the product of the force by the time of its action. The change in the momentum of the body is equal to the product of the force by the time of its action: (N s)

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Momentum conservation law

In a closed system, the vector sum of the impulses of all bodies included in the system remains constant for any interactions between the bodies of this system.

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Tsiolkovsky Konstantin Eduardovich (1857-1935)

Russian scientist and inventor, founder of modern cosmonautics. Proceedings in the field of aerodynamics and rocket dynamics, the theory of aircraft and airship.

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Application of the law of conservation of momentum

Recoil motion is based on the principle of recoil. In a rocket, during the combustion of fuel, gases heated to a high temperature are ejected from the nozzle at a high speed relative to the rocket.

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APPLICATION OF THE LAW OF CONSERVATION OF IMPULSE