Question

The two rotating systems shown below differ only in where two identical movable masses are positioned. On the left, they are positioned a distance r from the axis of rotation, and on the right, they are positioned at r/2 from the axis of rotation. If you release the hanging blocks simultaneously from rest at the same height,

A) the block at left lands first.

B) the block at right lands first.

C) both blocks land at the same time.

D) it is impossible to tell which block reaches the bottom first.

Answer 1

The block positioned at r/2 from the axis of rotation will land first.

Step-by-step explanation:

The answer to this question is B) the block at right lands first.

This can be explained using the principle of conservation of angular momentum. When the hanging blocks are released from rest at the same height, the block on the right will reach the ground first because it has a smaller distance from the axis of rotation. This means it has a smaller moment of inertia, which results in a higher angular velocity and faster rotation. Therefore, it will hit the ground first.