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Homework Help: Transverse standing wave?

  1. Feb 21, 2010 #1
    1. The problem statement, all variables and given/known data
    When mass M is tied to the bottom of a long, thin wire suspended from the ceiling, the wire's second-harmonic frequency is 200 Hz. Adding an additional 1kg to the hanging mass increases the second-harmonic frequency to 245 Hz. What is M?
    f[tex]_{2}[/tex] = 200hz, m = M
    f[tex]_{2}[/tex] = 245hz, m = M+1
    g = 9.8m/s

    2. Relevant equations
    f=v/L, v = [tex]\sqrt{T/u}[/tex]

    3. The attempt at a solution
    not sure where to start the problem
    please help!
    any help is greatly appreciated!
  2. jcsd
  3. Feb 21, 2010 #2
    Just did some plug and chuck with the equation f = v/L, substituted v = sqrt(T/u), T=mg, u = m/L, m cancels out, L = 2.45x10^-4, does this sound right?
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