The outstretched hands and arms of a figure skater preparing for a spin can be considered a slender rod pivoting about an axis through its center. (See the figure below ) When the skater's hands and arms are brought in and wrapped around his body to execute the spin, the hands and arms can be considered a thin-walled hollow cylinder. His hands and arms have a combined mass of 8.50kg . When outstretched, they span 1.80m ; when wrapped, they form a cylinder of radius 25.0cm .
The moment of inertia about the axis of rotation of the remainder of his body is constant and equal to 0.450kg?m2. If the skater's original angular speed is 0.450rev/s, what is his final angular speed?
What is his final angular speed in rev/s??