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Homework Help: Finding Amplitude

  1. Nov 11, 2007 #1
    1. The problem statement, all variables and given/known data
    A guitar string is vibrating in its fundamental mode, with nodes at each end. The length of the segment of the string that is free to vibrate is 0.381 m. The maximum transverse acceleration of a point at the middle of the segment is 8600 m/s^2 and the maximum transverse velocity is 3.50 m/s.

    3. The attempt at a solution

    Now i thought i has calculated it correctly i got A= 10.35m

    I used the fundamental F = v/2l threw that into a= Aw^2

    This question is making me angry! can anyone help me out!! ? cheers! ;)
  2. jcsd
  3. Nov 11, 2007 #2
    What is the question?
  4. Nov 11, 2007 #3
    What is the amplitude of the standing wave?
  5. Nov 11, 2007 #4
    Are you familiar with the equation of a standing wave? If you are, then you can differentiate it once and equate it to your maximum velocity, and then equate your maximum acceleration to the second derivative of the standing wave equation. You can then find A and w.
  6. Nov 11, 2007 #5
    how do i go about differentiating the wave equation?

  7. Nov 11, 2007 #6
    Differentiate with respect to t, using the chain rule.
  8. Nov 11, 2007 #7
    can somebody please please, differentiate this for me as an example


    with respect to t, i'm losing my nut here! Feel so dumb

    thanks a bunch
  9. Nov 11, 2007 #8
    You can't find derivatives on your own?
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