A person on the edge of a roof throws a ball downward. It strikes the ground with 100 J of kinetic energy. The person throws an identical ball upward with the same initial speed, and this too falls to the ground. Neglecting air resistance, the second ball hits the ground with a kinetic energy of

Question

Quizplus · Accepted Answer

The kinetic energy of both balls when they hit the ground is the same because energy conservation ensures that the total mechanical energy (potential + kinetic) remains constant if air resistance is neglected. The initial conditions (height and speed) are the same, just in different directions, so the final kinetic energies are equal.

A Person on the Edge of a Roof Throws a Ball