|Class 11 Physics Rotational Motion||Theorem of parallel axis|
Theorem of parallel axis
Example: Given the moment of inertia of a disc of mass M and radius R about any of its diameters to be MR2/4, find its moment of inertia about an axis normal to the disc and passing through a point on its edge
We can apply Perpendicular axis theorem here on x axis & y axis and get I’, moment of inertia in z axis.
Iz = Ix + Iy , now as because of symmetry Ix & Iy are same so Iz = I’ = 2I = Mr2/2
Now we can apply parallel axis theorem to find I’’.
I’’ = I’ + MR2 = 3/2(MR2)