A 65 kg student sits on a frictionless rotating stool
PHYSICS · Subjective · AP · Physics 1: Algebra-based · Energy and Momentum of Rotating Systems · Energy and Momentum of Rotating Systems
Problem
A 65 kg student sits on a frictionless rotating stool. With arms outstretched, he holds two 5.0 kg dumbbells, each 0.75 m from the axis of rotation. The student–stool system (excluding the dumbbells) has a moment of inertia of 3.0 kg·m². The system initially rotates at 0.60 rad/s. The student then pulls the dumbbells to 0.30 m from the axis. Determine the angular speed of the system after the dumbbells are pulled inward.