The moment of inertia expresses the ease of rotation of a rotating body, and is expressed by the following formula.
For example, if the inertia is small, the rotating body is easy to rotate and stop, but if the inertia is large, the rotating body is difficult to rotate and stop.

■Relationship between torque, angular velocity, and inertia

Torque is proportional to inertia and angular acceleration and is expressed below.
This has the same relational expression to Newton's law F = ma, only the variables have changed.

■Confirm the influence of inertia by simulation

See how inertia affects the movement of the rotating body. The above equation (1) is designed with scilab as follows.

The simulation results are as follows. It simulates the movement of angular velocity when the same torque is applied to rotating bodies with different inertia.
Even if the same torque is applied, the larger the inertia, the slower the speed rise.