Problem 1- A 0.5 kg ball is moving to the right at 5 m/s when it is suddenly collide by a wall that exerts on it a horizontal force of 2.5 N for a period of 0.8 s.

Question

a) What is the impulse does the force of the wall exert on the ball?
b) What is the velocity of the ball after the collision?

Answer 1

impulse = change of momentum
= average force * time
= -2.5*.8 = -2 N s = - 2 kg m/s

original momentum = .5*5 = 2.5 kg m/s

final momentum = original momentum + impulse
= 2.5 - 2 = .5
It broke through the wall and is still going right
m v = .5
.5 v = .5
v = 1 m/s