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Homework Help: Sound and wave homework

  1. Jun 9, 2014 #1
    1. The problem statement, all variables and given/known data
    A tuned violin, with strings of 31.6 cm each, is placed in front of a speaker. When varying the speakers frequency between 500 and 1500 Hz, it was discovered that a certain string only vibrated at 880 Hz and 1320 Hz. Determine the velocity of the wave in this string.

    2. Relevant equations

    3. The attempt at a solution
    The frequencies has to be overtones or the fundamental tone f_0. That gives nf_0=880 Hz and (n+1)f_0=1320 Hz, so n=2 and f_0=440 Hz. When f=f_0 the string has two nodes so v=f_0*2l (l=0.316m). v=278.08. But the key says 275 m/s, did I do something wrong or have they rounded it weirdly? Thanks
    Last edited: Jun 9, 2014
  2. jcsd
  3. Jun 9, 2014 #2
    I don't see anything wrong in your solution. It most probably is a case of rounding off weirdly.
    Last edited: Jun 9, 2014
  4. Jun 10, 2014 #3
    Yes, has to be so. Thanks :)
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