Rotational Kinetic Energy Calculator
Enter the moment of inertia and the angular velocity to find the rotational kinetic energy, KE = 1/2 x I x omega^2, in joules.
How to use the rotational kinetic energy calculator
- Enter the moment of inertia in kg x m^2.
- Enter the angular velocity in rad/s.
- Read the rotational kinetic energy in joules.
Examples
Spinning disk
I = 0.1 kg x m^2, omega = 10 rad/s
KE = 5 J
Heavier rotor
I = 2 kg x m^2, omega = 3 rad/s
KE = 9 J
Frequently asked questions
What is the rotational kinetic energy formula?
Rotational kinetic energy is KE = 1/2 x I x omega^2, where I is the moment of inertia in kg x m^2 and omega is the angular velocity in rad/s.
How is it different from linear kinetic energy?
Linear energy uses mass and speed, 1/2 m v^2. Rotational energy swaps in the moment of inertia for mass and the angular velocity for speed.
Where do I get the moment of inertia?
Use a moment of inertia calculator for the shape, such as 1/2 m r^2 for a disk. It captures how the mass is spread out from the axis.
Does the direction of spin matter?
No. Because omega is squared, clockwise and counterclockwise spin at the same rate give the same kinetic energy.
What units does the result use?
With the moment of inertia in kg x m^2 and the angular velocity in rad/s, the energy comes out in joules.
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