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Homework Help: Sipmle harmonic motion

  1. Dec 11, 2007 #1
    1. The problem statement, all variables and given/known data
    A horizontal plank (m = 2.0 kg, L = 1.0 m) is pivoted at one end. A spring. (k = 1000N/m) is attached at the other end find the angular frequence for small oscillations?

    2. Relevant equations

    3. The attempt at a solution

    w= (1000/2)^0.5
    i have no idea is this a pendulum problem i tried the w=(mgd/I)^0.5 and that also did not work. How do i go about this problem thanks
  2. jcsd
  3. Dec 12, 2007 #2


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    Homework Helper

    Weight of the plank acts through the CG of the plank.Clock wise moment due to this is 0.5*2*g. If the plank remains horizontal ,anticlockwise moment due to reaction in the spring = F*1 = F = mg = 0.5*2*g. So the spring appears to be stretched by a mass of 1 kg. using this value find w.
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