A locomotive moving at a constant speed approaches and then passes a man standing at a crossing.The frequency of the locomotive's horn as the man hears it
A)gradually increases and then decreases.
B)gradually decreases and then increases.
C)abruptly changes as the locomotive passes.
D)does not change at all.
E)produces beats due to the Doppler effect.

Question

Quizplus · Accepted Answer

As the locomotive approaches, the frequency of the horn appears higher due to the Doppler effect. As it passes and moves away, the frequency abruptly shifts to a lower value.

A Locomotive Moving at a Constant Speed Approaches and Then