A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How does the period of the pendulum change when the elevator
Moves downward with constant acceleration?
A) The period increases.
B) The period does not change.
C) The period increases if the upward acceleration is more than g/2 but decreases if the upward acceleration is less than g/2.
D) The period decreases.
E) The period becomes zero.

Question

Quizplus · Accepted Answer

When the elevator moves downward with constant acceleration, the effective acceleration due to gravity (g') experienced by the pendulum is reduced. Since the period of a pendulum $T = 2\pi\sqrt{\frac{L}{g'}}$, a decrease in g' leads to an increase in the period T.

A Pendulum of Length L Is Suspended from the Ceiling