Question

Assume that a 15-kg ball moving at 8m/s strikes a wall perpendicularly and rebounds elastically at the same speed. What is the amount of impulse given to the wall? Explain.

Answer 1

Impulse is change in momentum.

Find the change in velocity of the ball.

Answer 2

∆v = a∆t?

Answer 3

No.

The ball is initially travelling 8 m/s towards the wall.

Then it's travelling 8 m/s *away* from the wall.

Choose one direction to be positive.

Change in velocity is final velocity minus initial velocity.