A ball drops some distance and gains 30 J of kinetic energy. Do not ignore air resistance. How much gravitational potential energy did the ball lose?

Question

Quizplus · Accepted Answer

When the ball drops, some of its potential energy is converted into kinetic energy as it gains speed. However, since air resistance is not ignored, some energy is also lost to friction with the air. This means that the total energy of the system (the ball and the Earth) is not conserved. Therefore, the ball must have lost more than 30 J of gravitational potential energy, since some of that energy was lost to air resistance.

A Ball Drops Some Distance and Gains 30 J of Kinetic