Throwing Balls 3

You are initially at rest on a cart which has a single rigid wall on its left end. There is no friction between the cart and the ground. You throw a ball at the wall which bounces straight back and leaves the cart to the right. The cart (by conservation of momentum) goes to the left. Since everything (ball, cart, and person) began at rest and is now in motion, the kinetic energy of the system increased. Where did this energy come from?

A) Work

B) Heat

C) Thermal energy

D) Potential energy

E) Chemical energy

F) Other or can't tell

Solution