# Angular Momentum

1. Nov 20, 2009

### joebob

1. The problem statement, all variables and given/known data
An ice skater with a mass of 55.5kg is holding on to the end of a 3.75 m long rope tha is attached to a pole protruding out of a frictionless ice covered pond. Intially the skater is making one revolution every 5.44seconds.
What is the initial angular momentum of the skater?

A) 780kg m2/s
B) 901kg m2/s
c) 11,200 kg m2/s
d) 18600 kg m2/s
2. Relevant equations

3. The attempt at a solution
I have found the moment of interia, which i found to be 780.47kg m2
I found the angular velocity to be 1.13rad/s
The answer i get is not one of the options. I get 881.93kg m2/s
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Nov 20, 2009

### ideasrule

It's just a rounding error.

3. Nov 20, 2009

### joebob

What step is my error in? i have been redoing to equations and keep getting the same

4. Nov 20, 2009

### ideasrule

Angular velocity is more like 1.15 rads/sec. How did you get 1.13? 1 rev=2*pi, and 2*pi/5.44=1.155 rad/sec

5. Nov 20, 2009

### joebob

i did x/1=1/5.44 to get .18revolutions a second and then multiplied that by 2pie to convert to radians a second
i found my error while doing this it was a rounding error thanks for the help