Does Motion Affect Frequency in Sound Waves?

[scott_alexsk]

Hello,

The reason for the shifting of freqeuncies of all types of waves in response to relative motion away or towards the center of propagation, is caused by a corresponding stretching or compressing of the medium, correct? I mean for sound, if one moves toward the place where the sound orginates, then does not the motion of the person slightly increase the density of the air in front of them changing the frequency of the sound waves that travels through the air.

Thanks,
-scott

 

[Claude Bile]

If you are moving toward a source, you actually 'see' a higher frequency because you receive more cycles per second than if you were stationary with respect to the source - and vice-versa for the case where you are moving away from the source.

Density tends to affect the wavelength and velocity of a wave rather than the frequency, which is usually constant.

Claude.

 

[scott_alexsk]

According to my understanding frequency is the wavelength or atleast represents something that would be directly affected by it. I am not sure about sound though.

-scott