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Homework Help: What is the phase difference between the motions of two points on the wave

  1. May 11, 2008 #1
    [SOLVED] What is the phase difference between the motions of two points on the wave..

    1. The problem statement, all variables and given/known data
    The frequency of a certain wave is [tex]500Hz[/tex] and its speed is [tex]340ms^{-1}[/tex].What is the phase difference between the motions of two points on the wave [tex]0.17cm[/tex] apart?

    2. Relevant equations
    [tex]x = \frac{d\lambda}{a}[/tex]

    [tex]v = f\lambda[/tex]

    3. The attempt at a solution

    [tex]f = 500Hz \ \ \ v = 340ms^{-1} \ \ \ a = 0.17 \times 10^{-2} cm[/tex]

    [tex]v = f\lambda[/tex]

    [tex]\lambda = \frac{v}{f} = \frac{340}{500} = 0.68m[/tex]

    What should I do next?
     
    Last edited: May 11, 2008
  2. jcsd
  3. May 11, 2008 #2

    Kurdt

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    Two points 0.68cm apart will be out of phase by 360 degrees.
     
  4. May 11, 2008 #3
    Two points [itex]\lambda[/itex] apart will be out of phase by 360 deg.

    Regards,

    Bill
     
  5. May 11, 2008 #4

    Kurdt

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    In this case that is 0.68m. Damn I just realised I said cm, but you know what I mean. :tongue:
     
  6. May 12, 2008 #5
    So, the answer is = 0.68m by 360° ?
     
  7. May 12, 2008 #6

    Gib Z

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    No, I won't be. You know the phase difference between points 0.68m apart is 360°, the question asks the phase difference for 0.17m, which happens to be a quarter the quantity of which we do know the phase difference for. Just one more step =]
     
  8. May 12, 2008 #7
    Define the terms in your first relevant equation - one of those terms should be what you solve for to get the answer.

    BTW - check what you wrote for "a" (cm?).

    Regards,

    Bill
     
  9. May 12, 2008 #8

    Kurdt

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    As GibZ alluded to, I was trying to coax you toward the right answer not just give you the answer outright (since that would be against forum policy).
     
  10. May 12, 2008 #9
    [tex]0.68m = 360^o[/tex]
    [tex]0.17m = x[/tex]

    [tex]x = \frac{0.17 \times 360}{0.68}[/tex]

    [tex]x = 90^o[/tex]

    So, the phase difference is [tex]90^o[/tex] ?
     
  11. May 12, 2008 #10

    Kurdt

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    Thats correct.
     
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