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Homework Help: Longitudinal waves

  1. Jan 28, 2009 #1
    Why is it that when a longitudinal wave is represented by a (pressure/position) and a (displacement/position) graph does the displacement 0 represent a compression or rarefaction
    (maximum or minimum pressure)?
  2. jcsd
  3. Jan 28, 2009 #2


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    Homework Helper

    You can think of it as the average of what the molecules are doing there. The compression peaks occur where the molecules are coming together, so the displacements of the molecules are all directed towards that point and they average out to zero. Similarly for rarefaction, except that they are direcected away from that point.
  4. Jan 29, 2009 #3
    thanks that clears it up
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