MOMENT OF INERTIA.

There are two types of Moments of inertia:

1-Area moment of inertia, an example for it is, the resistance of a beam to bend or deflect.

2-Mass moment of inertia, is the resistance of the geometry of a mass to do rotation or rolling.

For more info, I think you should check a classical mechanics book.

Hope I was helpful.

Maverick.

Take the example of FAN.

Case 1 : Put 25kg load on each wings near the axis of fan then start the fan.

Case 2 : Then after put same load on each wings away from the axis of fan i.e. at the ends of wings.

You relize that the fan will rotate with slow speed as compared to the case 1.

This difficulty to rotate with same speed is called MOMENT OF INERTIA.