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Power Supplied to a vibrating string

  1. Feb 28, 2013 #1
    1. The problem statement, all variables and given/known data
    I keep getting the wrong answer for this question:

    A taut spring for which μ = 0.05 kg/m is under tension of 80.0N. How much power must be supplied to the string to generate sinusoidal waves at a frequency of 60Hz and an amplitude of 6cm?

    2. Relevant equations
    ω = 2∏f
    v = √(T/μ)
    P = (1/2)μω2A2v

    3. The attempt at a solution
    Convert cm to m --> 6cm = 0.06m

    Find ω
    ω = 2∏(60)
    = 376.99

    Find v
    v = √(80/.05)

    Find P
    P = (1/2)(0.05)(376.99)2(0.06)2(0.4)

    however, the book tells me the answer is 512W. Did I convert something wrong?

    Watts is J/s, and joules is in (Kg * m2)/s, so it only makes sense that I would have to convert the cm to m.

    By dimensional analysis my answer has the units of :
    (kg * rad2 * m2) / s3
    Last edited: Feb 28, 2013
  2. jcsd
  3. Feb 28, 2013 #2


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    Check this part of your calculation.
  4. Feb 28, 2013 #3
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