# Lesson Worksheet: Rotational Kinetic Energy Physics • 9th Grade

In this worksheet, we will practice calculating the rotational kinetic energy of a rotating object from its moment of inertia and its angular velocity.

Q1:

Which of the following relations describes how the rotational kinetic energy, , of a rotating object varies with the moment of inertia, , of that object around its axis of rotation?

• A
• B
• C
• D
• E

Q2:

A baseball bat that is being swung to hit a baseball has rotational kinetic energy of 1,490 J and an angular velocity of 12.1 rad/s. What is the moment of inertia of the object around its axis of rotation? Give your answer to one decimal place.

Q3:

A rotating object has rotational kinetic energy of 4,000 J. A torque is applied to the object and 2,600 J of rotational work is done accelerating the object. If the object has a moment of inertia of , what is its angular velocity after the torque has been applied? Give your answer to one decimal place.

Q4:

A tennis ball has a rotational kinetic energy of 248 J. Its moment of inertia around its axis of rotation is 0.22 kg⋅m2. What is the angular velocity of the tennis ball? Give your answer to the nearest radian per second.

Q5:

An object has a rotational kinetic energy of 11,250 J. Its moment of inertia around its axis of rotation is 4.0 kg⋅m2. What is its angular velocity?

Q6:

A football is rotating with an angular velocity of 28 rad/s. The football has a moment of inertia of 1.9 kg⋅m2 around its axis of rotation. What is the rotational kinetic energy of the football? Give your answer to the nearest joule.

Q7:

A solid metal disk is rotating with an angular velocity of 15 rad/s. The disk has a moment of inertia of 4.0 kg⋅m2 around its axis of rotation. What is the rotational kinetic energy of the disk?

Q8:

Which of the following relations describes how the rotational kinetic energy, , of a rotating object varies with the angular velocity, , of that object?

• A
• B
• C
• D
• E

Q9:

An object has a rotational kinetic energy of 3,300 J and an angular velocity of 25.0 rad/s. What is the moment of inertia of the object around its axis of rotation? Give your answer to one decimal place.