Concept
Version 9
Created by Boundless
General Case

The Doppler Effect
The same sound source is radiating sound waves at a constant frequency in the same medium. However, now the sound source is moving to the right with a speed υs = 0.7 c (Mach 0.7). The wave-fronts are produced with the same frequency as before. However, since the source is moving, the centre of each new wavefront is now slightly displaced to the right. As a result, the wave-fronts begin to bunch up on the right side (in front of) and spread further apart on the left side (behind) of the source.
Source
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"Dopplereffectsourcemovingrightatmach0.7."
http://en.wikipedia.org/wiki/File:Dopplereffectsourcemovingrightatmach0.7.gif
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