Final answer:
The scale reading in the elevator is greater than the true weight of the books because it needs to push up with a force greater than their weight. When the elevator is moving at a constant velocity, the scale reading will be equal to the true weight of the books.
Step-by-step explanation:
The scale reading in the elevator is greater than the true weight of the books because the scale is pushing up on the books with a force greater than their weight. This is necessary in order to accelerate the books upward. When the elevator is moving with a constant velocity, whether it is moving up, moving down, or stationary, the scale reading will be equal to the true weight of the books. In this case, the scale reading will be 165 N.
When the scale reads 165 N in an elevator, it indicates the elevator is either stationary or moving at a constant velocity, as the scale shows the true weight of the stack of books.
If the scale reads 165 N while in an elevator, this means that the elevator is either stationary or moving at a constant velocity, whether it is going upwards or downwards. As long as the elevator is not accelerating, the scale will read the true weight of the stack of books, which in this case is 165 N. When the elevator accelerates, the scale reading would be different from the true weight due to the additional force required to change the velocity of the books.
When the elevator is moving at a constant velocity, the scale reading will be equal to the true weight of the books.