The body moves in a straight line. Under the action of a constant force of 4 N, the body impulse increased in 2

The body moves in a straight line. Under the action of a constant force of 4 N, the body impulse increased in 2 s and became equal to 20 kg * m / s. The initial impulse of the body is.

F = 4 N.

t = 2 s.

p = 20 kg * m / s.

p0 -?

Let us write Newton’s 2 law for a body: F = m * a, where F is the force acting on the body, m is the mass of the body, and is the acceleration of the body.

Let us write the acceleration of the body a according to the formula: a = (V – V0) / t, where V is the final velocity of the body, V0 is the initial velocity of the body, t is the time during which the velocity changes.

2 Newton’s law will take the form: F = m * (V – V0) / t = (m * V – m * V0) / t.

The physical quantity equal to the product of the mass of the body m by the speed of its movement V is called the momentum of the body p.

F = (p – p0) / t – 2 Newton’s law through the momentum of the body, where p, p0 are the final and initial momentum of the body.

F * t = p – p0.

The formula for determining the initial momentum of the body p0 will have the form: p0 = p – F * t.

p0 = 20 kg * m / s – 4 N * 2 s = 12 kg * m / s.

Answer: the initial impulse of the body was p0 = 12 kg * m / s.