Rotational Kinetic Energy

When objects rotate we must introduce a new form of energy. Rotational Kinetic Energy is just another form of mechanical energy. In this case the energy is due to the moment of inertia of the object and the angular velocity. As with any other type of mechanical energy we can apply the conservation of energy to situations involving rotational kinetic energy. The actual equation for conservation of energy is now updated to include rotational kinetic energy. Please watch the following presentation that will discuss Rotational Kinetic Energy and update the Law of Conservation of Energy to include rotation.

Rotational Kinetic Energy Practice

Remember when solving these problems that objects can have both linear and rotational kinetic energy. If a object is rotating it must have rotational kinetic energy and if it is moving linearly then it must have linear kinetic energy.

Rotational Kinetic Energy Self-Assessment

A solid disk has a radius of 0.500 m and a mass of 2.00 kg. It is hung from a string and spins completely once every 0.250 s.
1. What is the moment of inertia of the disk?
2. What is the angular velocity of the disk?
3. What is the rotational kinetic energy of the disk?
4. -35.0 J work are done on the disk. What is the final rotational kinetic energy of the disk?
5. What is the final angular velocity of the disk?
The same solid disk, radius 0.500 and mass 2.00 is placed against a spring, k=250 N/m. The spring is compressed 0.500 m and released causing the disk to roll without slipping up a slope.
1. What is the initial mechanical energy of the disk?
2. What is the linear velocity of the disk when it is 1.00 m above its initial position?

SOLUTIONS FOR 1 & 2

Rotational Kinetic Energy Practice Problems

Download Rotational Kinetic Energy Practice Problems for more practice.

Download solutions to the practice problems.

VIDEOS CREATED BY GAVS

IMAGES SOURCED FROM PUBLIC DOMAIN