The
figure shows experssions for moment of inertia when the axis of rotation
is through the center of mass of the object. Two objects are considered.
The sphere and the cylinder. The
figure shows experssions for moment of inertia when the axis of rotation
is through the center of mass of the object. Two objects are considered.
The sphere and the cylinder.
For the cylinder, two different axes through the center of mass are considered: An axis along the central axis of the cylinder, and an axis perpendicular to the central axis of the cylinder.
If the moment of inertia for an axis through the center of mass is known, then the Parallel Axis Theorem allows calculation of the moment of inertia for any other axis which is paralle to the first.
In the equation, the new axis is labeled with a || subscript. D is the distance between the two axes, along any line perpendicular to them. m is the mass of the object.
Note that a wheel, a rod, and a barrel are all cylinders.