lordsavethee Posted February 9, 2006 Posted February 9, 2006 I do not understand how the wavelength of sound changes depending on the distance between the moving source and the observer. Its as if the sound waves have foresight as to how far the objects is and adjust wavelength. Please explain.
Royston Posted February 9, 2006 Posted February 9, 2006 This should answer your question... http://www.scienceforums.net/forums/showthread.php?t=7069&highlight=doppler+effect+sound
swansont Posted February 9, 2006 Posted February 9, 2006 This should answer your question... http://www.scienceforums.net/forums/showthread.php?t=7069&highlight=doppler+effect+sound That's really not a thread about the Doppler effect. Sound is a physical disturbance of molecules. But the measurement of the length and frequency of the wave depends on the speed of motion between source and observer. It is not a dependence on distance.
lordsavethee Posted February 9, 2006 Author Posted February 9, 2006 I got it clarified through a friend. The wavelength is the distance between two crests or troughs and when the source is moving towards the observer, the distance between subsequent crests is shortenend and hence the reduced wavelength. The frequency however is the same. Only the apparent frequency changes. Do you not agree?
5614 Posted February 9, 2006 Posted February 9, 2006 No. Because the wavelength has changed the frequency must also change. One formula to show this would be: [math]f \lambda = v[/math] Where: f = frequency [math]\lambda[/math] = wavelength v = velocity of the wave So when the wavelength decreases the frequency must increase so that the wave continues to move at a constant velocity. When two bodies are moving relative to each other it is the frequency change which makes you hear a sound at a different frequency to the source sound.
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