Physics

Albert Fisher

8 April, 01:29

The frequency of the sound waves detected by a detector is exactly equal to the frequency of the sound waves emitted by a source. What can we say about the relative motion of the detector and source?

A.

Both are at rest.

B.

Both are moving with the same velocity.

C.

They are moving with opposite velocities.

D.

Both are either at rest or moving with the same velocity.