In classical mechanics, the moment of inertia (also known as the mass moment of inertia) is usually expressed as I, and the SI unit is kg * m2, which can be said to be the inertia of an object for rotational motion. For a particle, \(I = mr^2\), where m is its mass and r is the vertical distance of the particle and the axis of rotation. The role of moment of inertia in rotational dynamics is equivalent to the mass in linear dynamics, describing the relationship between angular momentum, angular velocity, moment and angular acceleration.

The formula uses:

\(Moment of inertia = M * D^2\)

M = quality

D = vertical distance between the particle and the shaft