A ball hits a vertical wall horizontal at 10 m/s bounces back at 10 m/s

Options

A. There is no acceleration because `10m/s - 10m/s =0`
B. There may be an acceleration because its initial direction is horizontal
C. There is an acceleration because there is a momentum change
D. Even though there is no change in momentum there is a change in direction. Hence it has an acceleration

Answer

C

Explanation

Change in momentum = 2mv
Force = Rate of change of momentum hence force acts on the wall and their will be acceleration.