Conservation of Angular Momentum Question

  • Thread starter timtng
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  • #1
timtng
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An ice skater doing a toe spin with outstretched arms has an angular velocity of 4 rad/s. She then tucks in her arms, decreasing her moment of inertia by 7.5%

a. What is the resulting angular velocity?
b. By what factor does the skater's kinetic energy change?

For a, I use IW = I'W' >> 1(4rad/s) = (1-.075)W', then solve for W'
I got 4.32 rad/s for W'. I don't know if I'm doing it correctly. Also, I need help on part b.

Thx
 

Answers and Replies

  • #2
NateTG
Science Advisor
Homework Helper
2,452
7
Part a looks ok.

IIRC the formula for rotational energy is
1/2Iω2

The ratio is the old kinetic energy divided by the new kinetic energy.
 

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