Conservation of Angular Momentum Practice Test

A platform rotates with angular momentum $L_0$ about a vertical axis. External torque is negligible. A student moves from the center to the edge, increasing the system’s moment of inertia from $I$ to $2I$. What is the new angular momentum?

A person on a rotating stool holds two identical dumbbells. External torque on the person–stool system is negligible. The person moves the dumbbells farther from the rotation axis, increasing rotational inertia. What happens to angular speed?