I stared at this problem for 45 minutes trying to figure it out! It seems so easy, what am I missing? A figure skater during her finale can increase her rotation rate from an initial rate of 1.09 revolutions per 2.02 seconds to a final rate of 2.81 revolutions per second. If her initial moment of inertia was 4.77 kg*m^2, what is her final moment of intertia? So, what I have so far is that 1.09 rev/ 2.02 sec is .5396 rev/s and times 2pi that is 3.3904 radians per second. Or is it rad/sec^2? Do I assume from the problem that they mean that she is accelerating by 1.09 rev per every 2.02 seconds? That's what is confusing me. The final velocity is 2.81 rev/s times 2pi to equal 17.6557 rad/s. If that's acceleration, then I can use the equation Torque=Inertia times angular acceleration. But, my problem is, I don't know what to do with the problem, maybe it's because I've been thinking about physics for 6 hours or what, but I know I set two equations equal to each other to solve for final inertia. But what are these equations?? I would really appreciate any help. I'm at a loss for what to do.