Torque and Rotational Motion
Which quantity must be conserved in a closed system with no net external forces or torques?
Only thermal energy
Only gravitational potential energy
Only kinetic energy
Both linear and angular momenta
When a figure skater pulls in her arms while spinning, what happens to her rotational speed?
It decreases.
It reverses direction.
It increases.
It stays the same.
A student rotates a bike wheel at constant angular velocity and then releases it; if air resistance is negligible but friction at the axle is not zero how would you describe changes in kinetic energy as long as wheel turns?
Angular velocity increases as internal friction provides additional torque converting potential energy into rotational kinetic energy.
Rotational kinetic energy maintains constant while potential energy oscillates between maximums and minimums because there's no net force.
The total kinetic energy increases since conversion from static friction back to kinetic friction adds energy into the rotational system.
Total kinetic energy decreases since friction converts some rotational kinetic energy into thermal energy over time.
What kinematic formula links final angular velocity (), initial angular velocity (), angular acceleration (), and time ?
When a putty ball traveling horizontally hits and sticks to a hanging mass suspended by a string, causing it to swing upward, which quantity regarding the combined system remains constant throughout this interaction?
Total linear momentum
Total mechanical energy
Kinetic energy of both objects
Velocity of the putty ball
What happens to the rotational speed of a spinning wheel if its rotational inertia decreases while no net external torque acts on it?
There isn't enough information to determine what happens to the rotational speed.
The rotational speed increases.
The rotational speed decreases.
The rotational speed remains unchanged.
A point on a disk travels 12 radians around the center in 3 seconds. What was the angular velocity of the point?
2 rad/s
8 rad/s
4 rad/s
3 rad/s

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In a particle collider, a circular path, two charged particles traveling in opposite directions are identical in mass. One has twice the charge. How do their angular velocities compare after being released from the magnetic field?
The particle with less charge moves faster since it has a lower mass/charge ratio and experiences less resistance
The particle with greater charge has a higher angular velocity because it experiences greater force
They are the same because charge has no effect on angular velocity once particles are released
The twice-charged particle will stop first due to greater interaction with field lines leading to slower angular velocity after release
Which quantity measures an object’s resistance to changes in its rotational speed?
Moment of inertia
Angular momentum
Tangential speed
Centripetal acceleration
When comparing an object at sea level with another at twice this altitude above Earth's surface, which statement best describes how their weights compare given a constant mass?
Weight cannot be determined without knowing specific altitudes involved and Earth’s radius precisely as well as local variations in Earth’s density and shape such as mountains or valleys could affect measurements too much for a simple inverse-square law approximation.
The object at twice this altitude experiences less weight due to weaker gravity.
Both objects experience equal weights since their masses are equal.
The object at sea level experiences less weight because it is closer to Earth's center.