Derive the expression for moment of inertia of a circular disc
about the diameter of the disc.

Explanation

Let l, be the M.I, of disc about each diameter XX. and YY.. I be the M.I. of disc about an axis passing through the centre and perpendicular to the plane of the disc. According to the theorem of perpendicular axes, we get

`I_D+I_D= I " or " 2I_D = (MR^2)/(2) " or " I_D = (MR^2)/4`