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Help with something to do with angular stuff?

  1. Jan 16, 2008 #1
    A copper block rests 39.0 cm from the center of a steel turntable. The coefficient of static friction between the block and the surface is 0.34. The turntable starts from rest and rotates with a constant angular acceleration of 0.50 rad/s2. After what time interval will the block start to slip on the turntable? (Hint: The normal force in this case equals the weight of the block.)

    I seriously have no idea which formulas to use...Thanks!

    Last edited: Jan 16, 2008
  2. jcsd
  3. Jan 16, 2008 #2


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    Do you know how to calculate the centrifugal force on a rotating object?
  4. Jan 16, 2008 #3
    I only know how to do centripetal forces...

    Actually hold on...maybe
  5. Jan 16, 2008 #4
    I have down the formula:

    force that maintains circular motion=mrw^2

    If there was a way to find angular displacement, that would be helpful.
  6. Jan 16, 2008 #5
    If you're trying to confuse the poor lad, that's not very nice. Centrifugal force, as I'm sure you know, is a fictional force, which means, for the purposes of this thread, that it doesn't exist.
  7. Jan 16, 2008 #6
    Try doing a force body diagram.
  8. Jan 16, 2008 #7
    Ok...I'm trying to calculate what Fs is now...thanks!
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