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Homework Help: Rigid body dynamics: falling stick

  1. Apr 7, 2015 #1
    1. The problem statement, all variables and given/known data
    A stick of length L and mass m is falling on a table with kinetic friction uK and static friction uS. Find the equation that determines whether the rod will stick or slip.

    If m = 10kg and L = 100cm, uS = 0.8, uK = 0.7 and initial theta = 30 degrees find the initial accel for stick and slip.
    2. Relevant equations
    Irod = (1/3)mL^2
    M= r x F

    3. The attempt at a solution
    I'm so stuck.

    I made an FBD but as far as I can see, there are no forces in the X-direction, so what exactly makes the thing slip?
     
    Last edited: Apr 7, 2015
  2. jcsd
  3. Apr 7, 2015 #2
    From my FBD:

    Iα = -mg(L/2)Sinθ

    then α = -(3/2L)gsinθ

    so far so good?
     
  4. Apr 7, 2015 #3
    By which the translational x-acceleration of the rod must be (taking positive x to the left):

    Ax= -αRSinθ - uK*N / m

    correct?
     
  5. Apr 8, 2015 #4
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