Question

Find the radius of gyration of a uniform disc about an axis perpendicular to its plane

and passing through its center​

Answer 1

Moment of Inertia of disc about center of mass is I=mR^2/2

Let a line parallel to axis at a distance d.

Radius of Gyration=R

then,mR^2/2=mR^2

or,R^2=R^2/2

or, R=R/root 2