A girl of mass 50 kg throws a ball of mass 0.1 kg against a wall. The ball strikes the wall horizontally with a speed of 20 m/s, and it bounces back...

A girl of mass 50 kg throws a ball of mass 0.1 kg against a wall. The ball strikes the wall horizontally with a speed of 20 m/s, and it bounces back with this same speed. The ball is in contact with the wall 0.05s. What is the average force exerted on the wall by the ball?