Question

Diference between principle moment of inertia and moment of inertia

Answer 1

The moment of inertia,denoted l , is the rotational equivalent of mass:it is proportional to the amount of torque required for a given angular acceleration...For the sake of convenience , principal moments are defined, which correspond to the moment of inertia about the x,y and z axes in the body frame

Answer 2

Inertia is a force. Inertia is a force which keeps stationary objects at rest and moving objects in motion at constant velocity

An object would not have any inertia in a gravity-free environment (if there is such a place). Inertia is the tendency of all objects to resist motion and ultimately stop.