Answer to Question #93635 in Mechanics | Relativity for Simon

Question

Is it correct to say that on a moving train, although you hear the blowing horn pitch change while passing you at the station, the speed of propagation of the sound waves are the same before and after passes you?

Answer 1

Yes, It is correct

Reason behind it is doppler effect

Doppler effect is the change in frequency of the sound source when their is relative motion between source and listener

As the moving train approaches to you, the sound waves produced due to blowing horn get closer together, increasing their frequency and the pitch of the blowing horn. The opposite happens when the train moves away from you.

But the speed of the propagation of sound remain same while train passes you at the station.