Question

A 750-N man is standing on a bathroom scale in an elevator. When the elevator is moving, the man notices that the scale reads 780 N. Which statement correctly describes the motion of the elevator?

1) The elevator is moving upward with constant velocity
2) The elevator is moving upward with constant acceleration
3) The elevator is moving downward with constant velocity
4) The elevator is moving downward with constant acceleration

Answer 1

The scale reading indicates the elevator is accelerating upwards since the man's apparent weight is greater than his normal weight, implying the elevator is exerting additional force.

Step-by-step explanation:

When the elevator shows a scale reading greater than the man's normal weight (750 N), it indicates the elevator is exerting an additional force to accelerate the man upward. Since the scale reading is 780 N, which is above his static weight, we can deduce that the elevator is indeed accelerating upward, because if the elevator were moving at a constant velocity (upward or downward), the scale would read his normal weight, which is not the case here.

Therefore, the correct statement that describes the motion of the elevator, given that the scale reads 780 N, is that the elevator is moving upward with constant acceleration. This scenario matches Option 2 that was provided to us.