This Demonstration illustrates the parallel axis theorem for a solid cylinder. The parallel axis theorem states that , where is the moment of inertia of the object through the new axis, is the moment of inertia of the object through its center of mass, is the mass of the object, and is the perpendicular distance between the center of mass and the new axis. For a cylinder with an axis through the diameter of the shape, , where is the length of the cylinder. You can vary the length, radius, and mass of the cylinder, and the location of the axis in the - plane.