16. Angular Momentum

Two stars are observed from Earth to be separated by a distance $d$ on the sky, and they are both at a distance $D$ from Earth. What is the angular separation $\theta$ between the two stars in degrees?

The angular momentum of a particle is ____ its velocity $v$.

A solid disk of mass $m$ and radius $R$ is rotating about its central axis. At what angular velocity $\omega$ will its angular momentum be equal to $L$?

Two ladybugs, $A$ and $B$, are sitting at different distances from the center of a rotating turntable that spins at a constant rate. If both ladybugs are fixed to the turntable, how does the angular velocity of ladybug $A$ compare to that of ladybug $B$?

A solid disk of mass $m$ and radius $R$ rotates with angular velocity $\omega$ about its central axle. What is the angular momentum of the disk about the axle?

A uniform bar of mass $m$ and length $L$ rotates with angular velocity $\omega$ about an axle passing through one end and perpendicular to its length. What is the angular momentum of the bar about the axle?

Which physical principle best explains why already spinning nebula clumps flatten into discs during their evolution?

A wheel initially at rest is subjected to a constant net torque, causing it to accelerate with a constant angular acceleration of $2.0 \mathrm{rad}/s^2$. What is the angular velocity of the wheel at $15 s$?

Which of the following refers to the angle that is rotated in a given unit of time?

Why does the Sun rotate differently than solid objects such as a spinning disk or a wheel?

A salad spinner with a moment of inertia $I$ is spinning with an initial angular velocity ${\omega }_0$. If a constant frictional torque ${\tau }_f$ acts to slow it down, what is the magnitude of the angular acceleration $\alpha$ of the spinner?

A disk-shaped turntable of mass $M$ and radius $R$ is initially at rest. A small mass $m$ is dropped onto the edge of the turntable and sticks to it. If the mass lands tangentially with speed $v$, what is the angular velocity $\omega$ of the turntable and mass immediately after the collision?

Suppose you have four identical disks, each spinning about their central axis. Disk A rotates clockwise at $10 \mathrm{rad}/s$, Disk B rotates counterclockwise at $5 \mathrm{rad}/s$, Disk C is at rest, and Disk D rotates clockwise at $3 \mathrm{rad}/s$. If counterclockwise is defined as the positive direction, which of the disks have positive initial angular velocity?

A ball is moving in a horizontal circle on a frictionless table, attached to a string fixed at the center. If the ball moves counterclockwise when viewed from above, what is the direction of the angular momentum $\ell$ of the ball?

A CD with initial angular velocity ${\omega }_0$ is spinning on a frictional surface and comes to rest after a time $t$ with constant angular deceleration $\alpha$. How many revolutions does the CD make before stopping?