A decoration, of mass M, is suspended by a string from the ceiling inside an elevator. The elevator is traveling UPWARD with a constant speed. The tension in the string is
A) less than Mg.
B) equal to Mg.
C) greater than Mg.
D) impossible to tell without knowing the speed.
E) impossible to tell without knowing the decoration mass.

Question

Quizplus · Accepted Answer

When the elevator is moving upward with a constant speed, the decoration is in a state of equilibrium because there is no acceleration. Therefore, the tension in the string must exactly balance the gravitational force acting on the decoration, which is Mg.

A Decoration, of Mass M, Is Suspended by a String