A body is suspended from a spring hanging vertically. The body is then pulled downward so the spring stretches. Consider the change in the elastic potential energy (EPE) of the spring and the change in gravitational potential energy (GPE) as the body is pulled down.
A) The GPE decreases while the EPE increases.
B) The GPE decreases but the EPE is unchanged.
C) The EPE increases but the GPE is unchanged.
D) The GPE increases along with the EPE.
E) Both the GPE and the EPE decrease.

Question

Quizplus · Accepted Answer

As the body is pulled down, the distance between the body and the ground decreases, and thus the gravitational potential energy decreases. At the same time, the spring is stretched, and thus the elastic potential energy increases. Therefore, the GPE decreases while the EPE increases.

A Body Is Suspended from a Spring Hanging Vertically