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Homework Help: Conservation on Angular Momentum

  1. Apr 15, 2008 #1
    A figure skater during her finale can increase her rotation rate from an initial rate of 1.02 revolutions every 2.08 s to a final rate of 3.05 revolutions per second. If her initial moment of inertia was 4.50 kg*m2, what is her final moment of inertia?
  2. jcsd
  3. Apr 15, 2008 #2


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    What have you tried so far? Please show us your work.
  4. Apr 15, 2008 #3

    i'm bascially stuck
    i have no idea where to begin
  5. Apr 15, 2008 #4


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    Can you state what the equation for angular momentum is? What does your textbook say?
  6. Apr 15, 2008 #5

  7. Apr 15, 2008 #6
    but the inertia is I=(1/2)MR^2
  8. Apr 15, 2008 #7


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    You want this form

    [tex]L = I\omega [/tex]

    Is that one in your book? L is angular momentum, I is the moment of inertia, and [tex]\omega[/tex] is the angular speed.

    Maybe look around here to learn about it: http://hyperphysics.phy-astr.gsu.edu/hbase/conser.html#conamo

    You don't need this, since you were given the initial value of I directly in the question. You are trying to find the final value.

    So if angular momentum is conserved, what will your equation look like?
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