A student sitting on a frictionless rotating stool has rotational inertia 0.91kg?m2 about a vertical axis through her center of mass when her arms are tight to her chest. The stool rotates at 7.25rad/s and has negligible mass. The student extends her arms until her hands, each holding a 4.7kg mass, are 0.73m from the rotation axis.
a.) Ignoring her arm mass, what's her new rotational velocity?
b.) Repeat if each arm is modeled as a 0.73m long uniform rod of mass of 4.8kg and her total body mass is 59kg .