Phoenix Business Daily

What is the moment of inertia of the rotating disk?

An energy storage system based on a flywheel (a rotating disk) can store a maximum of 4.8 MJ when the flywheel is rotating at 19,600 revolutions per minute. What is the moment of inertia of the flywheel?

Public Comments

1. Rotational energy (E) equals 1/2 I w^2 where I is moment of inertia. and w is angular velocity Rearrange the equation to solve for I E = 1/2 I w^2 2 E/w^2 = I Convert rpm to rad/sec. There's 2 pi radians per revolution. There's 60 sec in a minute 2 ( 4.8 MJ)/(19,600 rpm * 2pi/60) = I (9.6 MJ)/(2052.5 rad/sec) = I 4677 kg-m^2 = I
2. 1/4 MR^2