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Homework Help: Motion of an object attached to a spring

  1. Dec 10, 2007 #1
    1. The problem statement, all variables and given/known data
    A body of mass 5.0 kg is suspended by a spring which stretches 10 cm when the mass is attached. It is then displaced downward an additional 5.0 cm and released. Its position as a function of time is approximately?

    2. Relevant equations
    X(t) = Acos(wt+φ)

    3. The attempt at a solution
    the awnser to this problem is 0.05cos10t. I see where they get the 0.05 from since it is the amplitude but how do they figure out w(angular frequency)=10
  2. jcsd
  3. Dec 10, 2007 #2
    w = sqrt (k/m)

    F = -kx

    Now you have the equations you need
  4. Dec 10, 2007 #3
    how do i figure out F acceleration is not given
  5. Dec 10, 2007 #4
    F = -kx

    is Hooke's Law.

    The force comes from the weight of the body. And x is the extension of a spring.

    Use this to find k.

    Then apply the other formula to find w.
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