A girl of mass 55 kg throws a ball of mass 0.8 kg against a wall. The ball strikes the wall horizontally with a speed of 25 m/s, and it bounces back with the same speed. The ball is in contact with the wall 0.05 s. What is the average force exerted on the wall by the ball?

Question

A) 400 N
B) 800 N
C) 55,000 N
D) 27,500 N
E) 13,750 N

Answer 1

(Avg force) x (contact time) = momentum change
= 55*50 kg*m/s

Avg. force = 0.8*50/.05 = ____ N

One of the choices works.

Answer 2

800N

Answer 3

400

Answer 4

15