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Homework Help: Cyclic frequency of unknown weight

  1. Nov 17, 2005 #1
    When an unknown weight W was suspended from a spring with an unknown force constant k, it reached its equilibrium position and the spring was stretched 14.2cm because of the weight W. Then the weight W was pulled further down to a position 16cm (1.8cm below its equilibrium position) and released, which caused an oscillation in the spring. Calculate the cyclic frequency of the resulting motion. Answer in Hz.

    I set k=F/x:
    k=9.8m/.018 = 544.44m

    I used T=2π√(m/k) to solve for the period:
    T=2π√(m/544.44m) = .269s The mass canceled out

    I did 1/T for frequency:
    1/.269 = 3.714Hz

    The answer is wrong. I think it might have something to do with the 14.2cm information but I don't know how to incorporate it in the problem.
  2. jcsd
  3. Nov 17, 2005 #2


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    Science Advisor
    Homework Helper

    You need to use the 14.2 cm to calculate the spring constant.
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