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Homework Help: Accoustic problem

  1. May 7, 2006 #1
    The human tympanum is displaced by sound waves. This displacement is linked to the acting force by the equation:

    F = 4x

    where x is the displacement in meters.

    A wave of frequency 1000 Hz provoques a displacement of 1.5 x 10^-5 m. Prove that the energy given to the tympanum is given in 0.25*10^-3 s. Also find the average power of the wave.

    I don't how power is linked to frequency and energy in therms of waves...
    Last edited: May 7, 2006
  2. jcsd
  3. May 8, 2006 #2


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    Homework Helper

    The intensity of a wave is defined as
    where [itex]P[/itex] is its power (the amount of energy it transports per second) through a (perpendicular) cross sectional area [itex]S[/itex].

    The intensity is given by
    [tex]I=2\pi^2v\rho f^2A^2[/tex]
    which includes the propagation speed of the wave, [itex]v[/itex], while it is travelling throught a medium of density [itex]\rho[/itex], creating a disturbance with a frequency [itex]f[/itex] and amplitude [itex]A[/itex].
    Last edited: May 8, 2006
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