Parallel Axis Theorem


This illustrates the parallel Axis Theorem for a rectangular area. The Moment of Inertia ( Second Moment of Area ) of a rectangle about an axis parallel to the x axis is shown. The graph on the right shows how the moment varies with location of the axis. The rectangle width (a) and height (b) as well as the location of the axis can be varied with the sliders. The radius of Gyration, kx , is also shown for the axis. As the axis moves further from the centroid what happens to the radius of gyration?