The parallel axis theorem (sometimes called Steiner's theorem) relates the moment of inertia Icm about an axis A passing through the center of mass to the moment of inertia I a...The parallel axis theorem (sometimes called Steiner's theorem) relates the moment of inertia Icm about an axis A passing through the center of mass to the moment of inertia I about another axis parallel to A. Using the parallel axis theorem, find the moment of inertia of a rod of mass M and length L about an axis perpendicular to the rod and passing through one end.