Rotating Systems: Energy & Momentum
Which of the following best describes rotational kinetic energy?
The energy an object possesses due to its linear motion.
The energy an object possesses due to its rotation.
The potential energy stored in a rotating object.
The energy an object possesses due to its temperature.
A spinning top has a rotational inertia of and an angular velocity of . What is its rotational kinetic energy?
A solid sphere with a mass of and a radius of is rotating at . Given that the moment of inertia of a solid sphere is , what is its rotational kinetic energy?
A wheel with a moment of inertia of and a radius of is rolling without slipping at a linear speed of . What is its total kinetic energy?
A solid cylinder with mass and radius rolls down an incline of height without slipping. What is its speed at the bottom of the incline?
A motor applies a constant torque of to a flywheel with a moment of inertia of . If the flywheel starts from rest, what is its rotational kinetic energy after 5 seconds?
A skater spins with her arms extended. When she pulls her arms in, her moment of inertia decreases. How does her rotational kinetic energy change, assuming no external torques?
It decreases.
It remains constant.
It increases.
It becomes zero.

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Rotational kinetic energy is a scalar quantity. What does this imply for calculations involving rotational kinetic energy?
It has both magnitude and direction, so directional components must be considered.
It has magnitude but no direction, so it can be added directly without considering direction.
It is always negative.
It can only be used for objects rotating in a clockwise direction.
Which of the following is a common mistake to avoid when calculating rotational kinetic energy?
Using the correct moment of inertia for the shape.
Ensuring angular velocity is in radians per second.
Including translational kinetic energy when present.
All of the above.
What happens to the rotational kinetic energy of an object if its angular velocity is doubled, assuming the moment of inertia remains constant?
It doubles.
It quadruples.
It remains the same.
It halves.