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FBD Friction Confusion

  1. Feb 5, 2012 #1
  2. jcsd
  3. Feb 5, 2012 #2

    SammyS

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    Is there some information you're not letting us in on? For instance, is the turntable undergoing negative angular acceleration?
     
  4. Feb 5, 2012 #3
    The turntable is actually undergoing positive angular acceleration with its motion shown counter-clockwise.
    We're looking for the time it takes for the turntable to reach a speed great enough to break the cord, which can only sustain a maximum tension of 100 N. mu,s = 0.1 and the mass of the disk D is 3 kg.
     
  5. Feb 5, 2012 #4

    SammyS

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    Then friction must have a tangential component as well as a radial component as shown in the figure.
     
  6. Feb 5, 2012 #5
    Friction only has a tangential component as shown in the figure. The T in the radial component is the tension in the string. My question is: why is the friction force acting in the positive tangential direction, if friction opposes motion?
     
  7. Feb 8, 2012 #6
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