A baseball rolls across the grass until it eventually stops ... What happens to the ball's kinetic energy?
A. It changes to potential energy
B. It changes to thermal energy
C. It changes to friction

Question

A baseball rolls across the grass until it eventually stops ... What happens to the ball's kinetic energy? 
A. It changes to potential energy
B. It changes to thermal energy
C. It changes to friction

anonymous · Answer

The question is a bit tricky because it's worded poorly.  Friction is a force and not a sort of energy, but the friction force converts kinetic energy into thermal energy.  To see this, just rub your hand on your pants for a while.  Your hand should warm up.  The best answer to this question is B.  It is not C because energy is not converted TO friction.  Energy is converted BY friction.