Question

A 0.2 kg tennis ball travelling at a speed of 15 m s−1 to the right strikes a wall. The contact time is 0.2 seconds. What is the average force exerted by the wall on the ball if: (i) the ball comes to rest and (ii) the ball travels in the opposite direction with the same speed?

Answer 1

(i)F=15N

(ii) F=30N

Explanation:

(i)when the ball comes to rest.i.e v=0

F=mv-mu/t

F=0.2×15/0.2

F=15N

(ii)when the ball rebonds with same speed then v=u

F=2mvcos180/t

F=2×0.2×15/0.2

F=30N