Conservation of Angular Momentum Question

  • Thread starter timtng
  • Start date
  • #1
25
0
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
2,450
5
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.
 

Related Threads on Conservation of Angular Momentum Question

Replies
2
Views
1K
Replies
1
Views
1K
Replies
8
Views
5K
Replies
5
Views
7K
Replies
2
Views
2K
Replies
6
Views
6K
Replies
1
Views
2K
Replies
3
Views
842
Replies
17
Views
756
Replies
7
Views
980
Top