Question

The moment of inertia of a circukar disc about ine of its diameters is I. What will be its moment of inertia of a tangent parallel to the diameter ?

Answer 1

The moment of inertia about an axis  perpendicular to the plane

Iplane=2* moment of inertia about diameter

I plane=2I

let m is the mass of the disc and r is the radius of the disc

I tan=2I+mr^2

I=mr^2/4

I tan=2*mr^2/4+mr^2

=6I