Rotating Systems: Energy & Momentum

A figure skater is spinning with her arms extended. If she suddenly pulls her arms in closer to her body, what happens to her angular velocity?

A spinning wheel has a moment of inertia of $2 kg cdot m^2$ and an angular velocity of $5 rad/s$. What is its angular momentum?

Two disks are rotating about the same axis. Disk A has a moment of inertia $I$ and angular velocity $\omega$. Disk B has a moment of inertia $2I$ and angular velocity $\omega/2$. If the two disks are brought into contact and rotate together, what is the total angular momentum of the system?

A small ball is thrown past a fixed point. Which of the following changes would increase the ball's angular momentum about that point?

A 0.5 kg ball is moving at 4 m/s. At a specific instant, it is 2 meters away from a reference point, and the angle between its velocity vector and the line connecting it to the reference point is 90 degrees. What is the angular momentum of the ball with respect to the reference point at that instant?

A projectile is launched and its angular momentum is calculated with respect to the launch point. How does the projectile's angular momentum change during its flight?

What is angular impulse?

A constant torque of 20 Nm is applied to a rotating object for 5 seconds. What is the angular impulse?

A graph of torque vs. time for a rotating object is shown below. The graph is a rectangle with a constant torque of 10 Nm from t = 0 to t = 4 seconds. What is the angular impulse applied to the object?

A complex torque vs. time graph requires integration to find the angular impulse. What does the integral of torque with respect to time represent?