Question

an elevator is moving down with a constant speed. inside the elevator, there is a block of mass m hanging from a rope with length ( x_1 ). the elevator then gradually slows to a stop with constant acceleration.

1. which statement is true when the elevator is moving down and gradually slowing down?

a. the block has an upward acceleration.
b. the block has a downward acceleration.
c. the block has an acceleration of 0.
d. the acceleration of the block keeps changing directions.

Explanation:

The elevator is moving down but slowing down, so its acceleration is opposite to its velocity direction. Since velocity is downward, acceleration is upward. The block moves with the elevator, so it has the same acceleration as the elevator. Thus, the block has an upward acceleration. Option a is correct. Options b (downward acceleration) is wrong as acceleration opposes velocity. Option c (acceleration 0) is wrong because the elevator is slowing, so acceleration isn't zero. Option d (changing acceleration direction) is wrong as acceleration is constant (given constant acceleration) and upward here.

Answer:

a. The block has an upward acceleration.