Energy and Momentum of Rotating Systems Quiz

A figure skater spins with her arms extended and then pulls them close to her body. Which statement best explains why she spins faster?

• The law of conservation of linear momentum

• The law of conservation of angular momentum

• A decrease in her moment of inertia creates torque

• An increase in her rotational kinetic energy creates force

The total kinetic energy of a rolling ball includes:

• Only rotational energy about its center of mass

• Only translational energy of its center of mass

• The sum of rotational and translational energies

• The product of rotational and translational energies

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NGSS.HS-PS3-2

A spinning flywheel slows down due to friction. This represents:

• Conservation of angular momentum

• An application of angular impulse

• A violation of Newton's first law

• Conservation of rotational energy

When comparing work done by torque, which combination would produce the same amount of work? if W=τθ

• Double the torque and double the angular displacement

• Half the torque and double the angular displacement

• Double the torque and half the angular displacement

• Double the torque and quarter the angular displacement

What happens to a rolling object's angular momentum if the reference point for rotation is changed?

• It always remains exactly the same

• The numerical value changes but total angular momentum is conserved

• It becomes zero at certain reference points

• It doubles with each change in reference point

A bowling ball is rolling without slipping. What is true about its motion?

• The point of contact with the ground has zero instantaneous velocity

• Kinetic friction is doing work on the ball

• The ball's translational speed is independent of its rotation

• The ball's total energy increases as it rolls

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NGSS.HS-PS3-2

In terms of energy efficiency, why is rolling without slipping preferable to rolling with slipping?

• Rolling without slipping requires less force

• Static friction does no work in pure rolling

• Rolling with slipping conserves more energy

• kinetic friction adds energy to the system

How does angular impulse relate to angular momentum?

• They are always equal

• Angular impulse causes a change in angular momentum

• They are inversely proportional

• Angular impulse is the square of angular momentum

Tags

NGSS.HS-PS2-2

For a rigid system, which statement about rotational kinetic energy is TRUE?

• It can only exist if the center of mass is moving

• It must be less than translational kinetic energy

• It can exist even when the center of mass is stationary

• It is always equal to translational kinetic energy

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NGSS.HS-PS3-2

A system's total angular momentum can change when:

• The system's mass distribution changes

• The system's rotation speed changes

• An external torque acts on the system

• The system's temperature changes