Question

You hold a small steel ball in your hand above a laundry basket. You throw the ball up from your hand and watch it as it rises and falls, and eventually comes to rest in the pile of laundry in the basket. Ignoring friction, discuss the forces exerted on the ball, the force displacement associated with those forces and the work done by each force during this process. You can consider the upward direction as positive.

Answer 1

First, the ball is always subjected to the force of gravity. It always acts downward. In the laundry, the "stopping" force does not let the ball reach the ground. We can say that this is a normal force. The force of gravity does positive work when the ball moves upward and the work done by gravity is negative while the ball is going down. As the ball hits the laundry pile, the normal force does positive work.