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Homework Help: Open-closed tube

  1. Apr 19, 2007 #1
    Here is my question:

    A 24.0 cm -long wire with a linear density of 20.0 g/m passes across the open end of an 89.0 cm-long open-closed tube of air. If the wire, which is fixed at both ends, vibrates at its fundamental frequency, the sound wave it generates excites the second vibrational mode of the tube of air. What is the tension in the wire? Assume v=340 m/s

    I am confused about the two values for the length. Do I have to use two equations and set them equal to each other? Would all else be the same for both? Please help :frown:
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Apr 19, 2007 #2
    yes you do need to use both lengths, what the systems have in common is frequency where the pipe is in its second vibrational mode, while the string is at its fundamental. Do you know what second mode means here?

    so write down some eqns, for both systems and we can go from there.
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