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Homework Help: Wave Equation problem Help

  1. Jan 25, 2006 #1
    Wave Equation problem..!!! Help...!!!

    Hi can anyone solve this??
    I couldnt figure out how to use it

    Question
    Use the wave equation to find the speed of wave given by

    y(x,t)=(3.00 mm) sin [(4.00/m)x-(7.0/s)t) ]





    I guess the wave equation is ,

    (d^2y) 1 (d^2y)
    ------- = ------ -------
    (dx^2) v^2 (dt^2)


    can any one solve it step wise?
     
  2. jcsd
  3. Jan 25, 2006 #2

    Päällikkö

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    Homework Helper

    Not really, no. That's not quite how stuff's done on this forum. You're supposed to do the work yourself.

    The wave equation:
    [tex]\frac{\partial ^2 y}{\partial x^2} = \frac{1}{v^2}\frac{\partial ^2 y}{\partial t^2}[/tex]

    For the given wave, can you solve
    [tex]\frac{\partial ^2 y}{\partial x^2}[/tex] and [tex]\frac{\partial ^2 y}{\partial t^2}[/tex] ?
     
  4. Jan 25, 2006 #3
    I mean need some hint......

    please I ahve 1 more hrs left
     
  5. Jan 25, 2006 #4
    Am i suppose to t6ake second derivative of whole equation...twice? once with respect to t and again with respect to x?
    is that how I am supposed to do?
     
  6. Jan 25, 2006 #5

    Päällikkö

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    Yep, that's what you're supposed to do.
     
  7. Jan 25, 2006 #6
    that means I am supposed to solve for "V" right?

    But the answer I got is not the same as the one I got from V=w/k

    ??
     
  8. Jan 25, 2006 #7

    Päällikkö

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    Homework Helper

    It should be the same, as the equation reduces to [tex]v = \frac{\omega}{k}[/tex]
     
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