angular deccelerartion

Discussion in 'Physics' started by braddy, Nov 2, 2005.

  1. braddy

    Thread Starter Well-Known Member

    Dec 29, 2004
    83
    0
    Hi,
    I need help with the following problem.

    A skater does a pirouette at the rate of 2.0 rev / second and then stop within 3/4 rev. Assume that the angular decceleration is constant and calculate its magnitude.

    I tried to compute it but I found -18 rad/s[sup]2[/sup].
    BUt the textbook gives -17 rad/s[sup]2[/sup].
    Please can someone help me with this problem?

    Thank you
    B
     
  2. m-rice

    New Member

    Nov 25, 2005
    2
    0
    Use the formula v^2 = u^2 + 2as, where v is final velocity (0), u is initial (2rev/sec) a is acceleration, and s is distance (0.75 rev)

    I get a = -16/6 rev/sec^2 = -16.755 rad/sec^2

    This is closer to the text book answer!

    Martin

    PS Did you manage to do the question about the spinning reel?
     
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