Question

which of the following could be your frame of reference if you are standing on the sidewalk and see the bus go by?
a stationary objects across the street.
b the clouds above your head.
c other cars moving on the street.
d a squirrel running through a tree nearby.

Explanation:

To determine the frame of reference where the bus is seen moving, we analyze each option:

• Option a: Stationary objects across the street. Relative to these, the bus (and you) are moving, so from this frame, the bus moves.
• Option b: Clouds above. Clouds are often moving, so the bus's motion relative to clouds is complex and not a clear frame to see the bus "go by" as you stand.
• Option c: Other moving cars. Their motion relative to the bus can vary, not a reliable frame to see the bus move as you stand.
• Option d: A squirrel in a tree. The squirrel's motion (if any) is independent, not a standard frame to observe the bus's motion as you stand.

The best frame is stationary objects across the street (option a) because they are fixed relative to your standing position, making the bus's motion observable.

Answer:

a. Stationary objects across the street.