A girl runs up a flight of stairs at a constant speed v, and the gain in her potential gravitational energy is U. When she runs up the same stairs at half that speed, the gain in her potential gravitational energy is
A) 0.
B) U/4.
C) U/2.
D) U.
E) 2U.

Question

Quizplus · Accepted Answer

The gain in potential gravitational energy depends only on the change in height, not on the speed of the climb, so it remains U regardless of how fast or slow she goes.

A Girl Runs Up a Flight of Stairs at a Constant