Rotating Systems: Energy & Momentum

A spinning ice skater pulls their arms inward during a spin. Assuming there is negligible external torque, what happens to the skater's angular momentum?

A rotating object has its moment of inertia reduced to one-third of its original value. If no external torque acts on the object, what is the new angular velocity in terms of its original angular velocity $\omega_0$?

A system consists of a rotating platform and a person standing at the center. The person then walks to the edge of the platform. During this process, both the moment of inertia of the system changes and there is friction at the axis of rotation. How do these factors interplay to affect the final angular velocity?

A solid disk with a moment of inertia of $2 , kg \cdot m^2$ is rotating at an angular velocity of $5 , rad/s$. What is the magnitude of its angular momentum?

Two identical disks are rotating about the same axis. Disk A has an angular momentum of $L$ and Disk B has an angular momentum of $2L$ in the same direction. What is the total angular momentum of the system?

In a binary star system, two stars orbit each other. Star A has mass $m_A$ and Star B has mass $m_B$. If the distance between them remains constant, and no external torques act on the system, what can be said about the total angular momentum of the system?

A wheel initially at rest experiences a constant external torque of $10 , N \cdot m$ for $5 , s$. What is the magnitude of the change in angular momentum of the wheel?

A spinning top is subject to a frictional torque. What effect does this torque have on the angular momentum of the top?

A student is sitting on a rotating stool holding a spinning bicycle wheel. The student turns the bicycle wheel upside down. For the system of the student and the wheel, is angular momentum conserved?

A rotating object collides with a stationary object, and they stick together. Which of the following is true about the angular momentum and kinetic energy of the system?