Help on Moment of inertia again thanks =D

[iamtrojan3]

Homework Statement

I need one more question answered =D thanks

A man is standing on a spinning turntable with a weight in each hand. His moment of inertia with arms outstretched is 16Nm. WIth his arms by his sdie his moment of Inertia is 6.4Nm. With arms outstreched he makes one rotation in 2 seconds. What is his angular velocity with his arms at his sides?

Homework Equations

i dont' even know where to start on this one

The Attempt at a Solution

none so far

 

[iamtrojan3]

no body knows? cry cry cry...

 

[aaroman]

Well, you should think if there is a torque acting on the man. If not, something might be conserved. You'll have to find out what, and write the equality between the quantity with arms outstretched and with arms on his side.