Question

a swimmer stands ready on a starting block. from which perspective would they appear to be moving? from the perspective of a fan in the stands from the perspective of the pool from the perspective of the sun

Explanation:

To determine if an object (the swimmer) is moving, we need to consider a reference frame. A reference frame is a set of coordinates that can be used to determine positions and velocities of objects in that frame.

• From the perspective of a fan in the stands: The fan and the swimmer are on the same Earth - based reference frame (assuming the fan is stationary in the stands). If the swimmer is just standing on the starting block (not yet moving), from the fan's perspective (in the same reference frame as the swimmer, neglecting Earth's rotation etc. on this small - scale), the swimmer is not moving.
• From the perspective of the pool: The pool is attached to the Earth (assuming it is a stationary pool). Similar to the fan in the stands (since the fan is in the stands which are attached to the Earth), if the swimmer is stationary on the block, from the pool's perspective (same Earth - based reference frame), the swimmer is not moving.
• From the perspective of the sun: The Earth is rotating about its axis and revolving around the sun. So, even if the swimmer is stationary on the starting block (with respect to the Earth - based reference frames like the fan in the stands and the pool), from the sun's perspective (a different reference frame), the swimmer is moving because the Earth (and everything on it, including the swimmer) is in motion (rotating and revolving).

Answer:

From the perspective of the sun