Question

A ball traveling in the +x direction hits the wall at 30m/s and rebounds at 25m/s. If the ball is in contact with the wall for 4ms, determine the average acceleration of the ball during this time interval.

Answer 1

The average acceleration of the ball during this time interval is simple change in speed divided by time it took:

$$a=\dfrac{v_f-v_i}{t}=\dfrac{-25-30}{0.004}=13750\text{ m/s}^2.$$