Question

what is the physical significance of moment of inertia? Please explain how it s helpful and what are the applications of moment of inertia?

Answer 1

Moment of inertia is the name given to rotational inertia, the rotational analog of mass for linear motion. It appears in the relationships for the dynamics of rotational motion. The moment of inertia must be specified with respect to a chosen axis of rotation. For a point mass the moment of inertia is just the mass times the square of perpendicular distance to the rotation axis, I = mr2. That point mass relationship becomes the basis for all other moments of inertia since any object can be built up from a collection of point masses.
For applications:Refer R,K,BANSAL's strength of materials.

Answer 2

moment of inertia has been used in civil engineering in two theories. once it has been used in bending beam theory and it has been used in buckling of beam problem. In both the cases its physical significance is different.
in bending theory, it gives the resistance of a beam to resist bending whereas in the other case, it is used to identify the buckling tendency of a beam.