A student is at rest on a stool that may freely spin about its central axis of rotation
PHYSICS · Subjective · AP · Physics 1: Algebra-based · Energy and Momentum of Rotating Systems · Energy and Momentum of Rotating Systems
Problem
A student is at rest on a stool that may freely spin about its central axis of rotation. As the stool spins, the student holds onto two dumbbells as the stool spins at an angular speed of 1.2 rad/s with the student's arms completely stretched out from the student's body. At this instant, the student-dumbbell system has rotational inertia of 6 kg⋅m2. The student then brings their arms close to their body, and rotational inertia of the student-dumbbell system is changed to 2 kg⋅m2.
What is the new angular speed of the student in rad/s? Express your answer to the nearest decimal point.