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Homework Help: Find New Frequency When Length AND Diameter Is Decreased?

  1. Jan 24, 2012 #1
    1. The problem statement, all variables and given/known data
    Hi, i need some help with this question,
    A string of length 60cm and diameter 0.80 mm is under tension 64 N. When plucked, it emits a frequency of 660Hz. What is the new frequency if the length is decreased to 40cm, the diameter decreased to 0.50mm and the tension increased to 100 N? Please explain, Thanks!

    2. Relevant equations
    f1/f2 = L2/L1, f1/f2 = Square Root F1/ Square Root F2, f1/f2 = d2/d1

    3. The attempt at a solution
    I can do it when one of the variables are decreased but i have no idea where to start when 3 variables are changing.
  2. jcsd
  3. Jan 24, 2012 #2

    Simon Bridge

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    Science Advisor
    Homework Helper

    The wave speed depends on the tension, the wavelength depends on the length of the string. Do each separately and combine to get frequency. The equation you are missing is v=fλ.
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