Rotational Inertia or Moment of Inertia

If we consider a rotating ridged object, such as a wheel, we can think of the wheel as consisting of many particles at various distances from the axis. Apply Torque for each particle:

is the same for each particle. is the moment of inertia, .

Which is the Rotational Motion equivalent of Newton’s second law. It plays the same role that mass does for translational motion. However, Moment of Inertia takes into consideration distance from the axis.

Which also means that:

Rotational Inertia of Solid Bodies