Question

A student sitting on a frictionless rotating stool has rotational inertia 0.92kg⋅m2 about a vertical axis through her center of mass when her arms are tight to her chest. The stool rotates at 7.40rad/s and has negligible mass. The student extends her arms until her hands, each holding a 4.4kg mass, are 0.78m from the rotation axis. Find rotational velocity if each arm is modeled as a 0.78m long uniform rod of mass of 4.5kg and her total body mass is 65kg .

Answer 1

Some how (1/3)ML^2 is involved

Answer 2

Conservation of angualr momentum!