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Homework Help: Spring Problem

  1. Nov 14, 2003 #1
    When the tension is 18 N, a string 2.00 m long has a fundamental frequency of 150 Hz.
    a.) What is the mass of the string?
    b.) With what tension must the string be stretched so that it vibrates in three segments at 150 Hz?

    This is what I came up with:
    a.) f=v/2L, v=2Lf=2*2*150=600 m/s
    v=sqrt(T/μ), v^2=T/μ, μ=T/v^2=18/600^2=.00005 kg/m
    M=2*.00005=.0001 kg

    b.) L=3λ/2, 2=3λ/2, λ=4/3
    v=fλ=150*4/3=200 m/s
    v^2=T/μ, T=μ*v^2=.00005*200^2=2 N

    Am I working both problems correctly?

    Thanks
     
  2. jcsd
  3. Nov 14, 2003 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Your physics looks good. (I didn't check the arithmetic :wink:)
     
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