Parallel Axis Theorem -- from Eric Weisstein's World of Physics

Let the vector describe the position of a point mass which is part of a conglomeration of such masses. Now write

where R is the vector to the center of mass of the body. If the body's moment of inertia tensor is , then the moment of inertia about an axis is given by

where Einstein summation Eric Weisstein's World of Math has been used to sum over point masses . Therefore, letting

be the moment of inertia about the axis , the moment of inertia can be expressed in terms of as

Capacitance, Capacitor

References