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Amplitude in an equation

  1. Feb 6, 2004 #1
    What does the [tex]A[/tex] stand for in the equation:

    [tex]y=A\sin{(kx-t\omega)}[/tex]



    CHEERS :)
     
  2. jcsd
  3. Feb 6, 2004 #2

    chroot

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    Amplitude.

    - Warren
     
  4. Feb 6, 2004 #3
    max value of the displacement from the mean position
     
  5. Feb 6, 2004 #4
    thanks :)

    but could you answer this

    whats the relationship between [tex]k[/tex] and the wavelength of the wave
     
  6. Feb 6, 2004 #5
    [tex]k=\frac{2\pi}{\lambda}[/tex]
     
  7. Feb 6, 2004 #6

    chroot

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    Think about it. If x is the displacement along a taught string, the wavelength of a wave on that string is the distance between successive crests or troughs.

    All sine waves repeat every 2 pi radians.

    When [itex]x = \lambda[/itex], you want the argument to be [itex]2 \pi[/itex].

    Try rewriting the first term (the term with the x) as:

    [tex]\frac{2 \pi x}{\lambda}[/tex]

    You'll see that when [itex]x = \lambda[/itex], the entire expression is [itex]2 \pi[/itex] -- exactly one period. This is the right expression.

    Therefore, if you want to simplify that expression by bringing in a new symbol k, k must be

    [tex]k = \frac{2 \pi}{\lambda}[/tex]

    - Warren
     
    Last edited: Feb 6, 2004
  8. Feb 6, 2004 #7
    Score! thanks Boudoir
     
  9. Feb 6, 2004 #8
    Bummer hit a brick wall again. check this out:

    for the equation [tex]y=A\sin{(kx-t\omega)}[/tex] find a relationship between [tex]\omega[/tex] and the time period [tex]T[/tex] of the wave.

    when [tex]t=T[/tex] [tex]y=0[/tex] and [tex]x=0[/tex]

    therefore:

    [tex]A\sin{(-T\omega)}=0[/tex]

    but then what?
     
  10. Feb 6, 2004 #9

    chroot

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    Don't you have a textbook?

    [tex]\omega = 2 \pi f[/tex]

    [tex]T = \frac{1}{f}[/tex]

    [tex]T = \frac{2 \pi}{\omega}[/tex]

    - Warren
     
  11. Feb 6, 2004 #10
    I think you're doing his homework for him.
     
  12. Feb 7, 2004 #11
    I dont find it as Homework.

    Anyway He is reaching the conclusions and thats the bottom line
     
  13. Feb 7, 2004 #12
    Thanks :smile: saved my life.
     
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