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Question on Vibration

  1. Jan 10, 2006 #1
    Hi all. (I've edited the question)
    As far as my intuition tells me, an underestimation of the damping effect would results in an overestimation of the magnification factor, am I correct?
    So I expect the experimental determined magnification factor for all frequency ratio to be smaller than the theoretical values given by the formula:
    [tex]R=\frac{1}{\sqrt{(1 - r^2)^2+(2r\zeta)^2}}[/tex]
    Because there would be extra damping due to the air resistance.

    However, it turned out that the experimental magnification factors are greater than the theoretical values! How come?

    Actually before exceeding the resonant frequency, the experimental values are greater than the theoretical values; after exceeding the resonant frequency a bit, the theoretical values are greater than the experimental values. How would you interpret this?
    I can just think of one thing: For high frequency ratio (exceeding the resonant frequency), the air resistance effect would be more significatns ince air resistance is proportional to the square of the velocity of the system.

    However, I have no idea on why the experimental values would be greater than the theoretical values, can anyone give some ideas?
    Last edited: Jan 10, 2006
  2. jcsd
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