The Parallel Axis Theorem provides a convenient way to calculate
the moment of inertia for an object about an different parallel axes. For
example, the moments of inertia of a thin rod about its center is different
from the moment of inertial about its end. The parallel axis theorem states
that the moment of inertia about an axis parallel to the axis passing through
the center of mass, and separated by a distance 
is
For the thin rod, the moment of inertia about an axis passing through its center of mass is
The result of applying the parallel axis theorem for rotation about the rod's end gives
.