Radius of gyration : It is defined as perpendicular distance between the axis of rotation and the point at which entire mass of the body is supposed to be conecntrated, so as to have the same moment of inertia as that of the body about the same axis of rotation.
Physical significance:
(i) The value of mass and radiys of gyration of the body about a given axis of rotation gives the value of its moment of inertia about the same axis, even, if we do not know the actual shape of the body.
(ii) The samll value of radius of gyration shows that hte mass of the body distributed close to the axis of rotation so that moment of inertia is small.
(iii) The large value of radiys of gyrations shows that hte maas of body is distributed at large distance from the axis of rotation and the moment of inertia is large.
