Significance of Moment of Inertia
Consider Equations (1) , (4) , (6) as above viz,
These equations are analogous to corresponding equations for a particle in translational motion.
analogous to 'm' ; hence the name
Moment of Inertia (M.I). It is the inertia of a rigid body in rotational motion about a fixed axis, i.e., the rigid
body cannot change its state of rotational motion about a given axis by itself due to its M.I.
The similarity pointed out above between translational motion of a particle and rotational motion of a
rigid body can be extended to any equation for the translational motion to the obtain corresponding
rotational motion equations,
The table below lists these similarities.
Note : For a discrete system of particles the where as for a continuous system of particles I =ò dm r2