having trouble with this physics question...please help!?

[odu83]

Treat the platform as a uniform disk
I=m*r^2/2
and the person as a point mass
I=m*r^2

using conservation of angular momentum
3.5*3.17^2(149.1/2+65.3)=
?*(149.1*3.17^2/2+65.3*2.03^2)

solve for ?

4.8 rad/s
______________-

[krisml4218]

A horizontal circular platform (m = 149.1 kg, r = 3.17m) rotates about a frictionless vertical axle. A student (m = 65.3kg) walks slowly from the rim of the platform toward the center. The angular velocity, omega, of the system is 3.5 rad/s when the student is at the rim. Find omega when the student is 2.03m from the center.