An elevator is moving upward with constant acceleration. The dashed curve shows the position y of the ceiling of the elevator as a function of the time t. At the instant indicated by the dot, a bolt breaks loose and drops from the ceiling. Which curve best represents the position of the bolt as a function of time?
A) A
B) B
C) C
D) D
E) E

Question

An elevator is moving upward with constant acceleration. The dashed curve shows the position y of the ceiling of the elevator as a function of the time t. At the instant indicated by the dot, a bolt breaks loose and drops from the ceiling. Which curve best represents the position of the bolt as a function of time? 
A) A 
B) B 
C) C 
D) D 
E) E

Quizplus · Accepted Answer

Since the elevator is moving upward with constant acceleration, and the bolt breaks loose from the ceiling, it is only under the influence of gravity. Therefore, the motion of the bolt is that of a freely falling object, which is represented by a parabolic curve. The correct curve should be one that starts at the same height as the dot and has the shape of a parabolic curve. Option B is the only curve that fits this description.

An Elevator Is Moving Upward with Constant Acceleration