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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?
     
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  3. Apr 15, 2008 #2

    hage567

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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

    hage567

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

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

    hage567

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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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