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What is the frequency of the signal?

  1. Mar 30, 2009 #1
    1. A water wave has a speed of 1.0 m/s. The distance between crests is 0.5 m. What is the
    wavenumber of the wave? If an observer at a fixed location measures the height h(t) of
    the wave that passes by, what is the frequency of the signal h(t)?




    2. k =2π/λ -> to get k= wavenumber

    h (t) = Acos (ωt − kz +φ)




    Hello, I need to do the above problem. I do have k( wavenumber). It's 12.56.

    I can move on to the second question now. The equation I would use is the second one above.

    ω = K*V.
    T should be 0.
    k is given now.

    How do I get A and φ ? It should be φ = −ψ. But I don't know how to get −ψ.

    ω could also be ω= 2πf But I don't know how to get f cause I don't have the Herz for the wave.

    I hope somebody can help me!

    Thank you!
     
    Last edited: Mar 30, 2009
  2. jcsd
  3. Mar 30, 2009 #2

    Redbelly98

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    Re: waves

    What equation relates frequency, wavelength, and wave speed?
     
  4. Mar 30, 2009 #3
    Re: waves

    Sorry, I don't get what you're trying to tell me. A might be the 0.5? Originally , I thought z was the 0.5.
     
    Last edited: Mar 30, 2009
  5. Mar 30, 2009 #4

    Redbelly98

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    Re: waves

    Forget A, that is the amplitude and is not needed here.

    Your text book should have an equation containing f, λ, and v (frequency, wavelength, and wave speed, respectively). You are given λ and v in the problem statement, so the equation I refer to can be used to calculate what the frequency f is.

    Again, you should be able to find it in your text book.
     
  6. Mar 30, 2009 #5
    Re: waves

    We don't have a text book. Just the notes provided by the teacher. And I tried every single equation, but I don't get it.
     
  7. Mar 30, 2009 #6

    Redbelly98

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  8. Mar 30, 2009 #7
    Re: waves

    Thank you! This one finally works:)
     
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