Question

A worker standing on the top of a moving train throws a ball straight up (in the train's reference frame). The ball rises to a height H and then, on the way down, is caught by the worker. In the reference frame of an observer standing on the platform the distance traveled by the ball on its round trip (being thrown up and then caught) is: [a] 2H [b] less than 21 [c] more than 2H.

Answer 1

In the reference frame of an observer standing on the platform, the distance traveled by the ball on its round trip is more than 2H.

Step-by-step explanation:

In the reference frame of an observer standing on the platform, the distance traveled by the ball on its round trip (being thrown up and then caught) is more than 2H.

This is because while the ball is in the air, the train is also moving forward, so the ball's horizontal velocity adds to the train's velocity. As a result, the ball covers a greater horizontal distance in the platform's reference frame compared to the train's reference frame. Therefore, the distance traveled by the ball in the platform's reference frame is greater than twice the height it rises in the train's frame, which is 2H.

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