Guide

1

motion of a particle is caused by exposure to certain

**forces or forces that give it acceleration.The result of the application of force****certain value for a certain time a corresponding amount of movement.Impulse****force is a measure of its validity over time: Pc = favg • Δt, gdeFsr - the average force acting on the body; Δt - time interval.** 2

Momentum is momentum

**body.It is a vector quantity, codirectional rate and equal to the product of its body weight: Pt = = m • v.** 3

Thus,

**momentum****force is changing****momentum and body: Pc = ΔPt = m • (v - v0), gdev0 - the initial velocity; v - the ultimate speed of the body.** 4

This equation shows Newton's second law with respect to an inertial reference frame: the derivative of a material point in time is e
qual to the value of the constant force acting on it: favg • Δt = ΔPt → favg = dPt / dt.

5

total

**momentum**of several bodies may change only under the influence of external forces, and its value is directly proportional to their amount.This is a consequence of the second and third laws of Newton.Suppose that the system consists of three interacting bodies, then right: Ps1 + Pc2 + Pc3 = ΔPt1 + + ΔPt3 ΔPt2, gdePci -**momentum****force**, acting on the body i; Pti -**momentum**body i. 6

This equation shows that if the sum of the external forces is zero, then the total momentum

**closed system of bodies is always constant, despite the fact that the internal force****change their momentum****s.This principle is called the law of conservation of momentum****well.It should be borne in mind that it is a vector sum.**

** ** 7

In reality, the system of bodies are rarely closed, since it always operates at least the force of gravity.It changes the momentum

**of vertical, but does not affect him, if the motion is horizontal.**

** ** Sources:

- how to find the strength to change