2mr25
mr22
mr25
mr2
To find the moment of inertia of a solid cylinder along its height, we can use the following method: If we compress the cylinder along its height (central axis), then it is converted into a disc but its mass distribution remains the same about the central axis. Hence its moment of inertia about its height is equal to the moment of inertia of the disc about an axis passing through its centre and perpendicular to its plane.
∴ ISolidCylinder = IDisc ⇒ ISolidCylinder = 1/2mr²