It is interesting to see how the moment of inertia varies with r, the distance to the axis of rotation of the mass particles in Equation ???. Rigid bodies and systems of particles with more ma...It is interesting to see how the moment of inertia varies with r, the distance to the axis of rotation of the mass particles in Equation ???. Rigid bodies and systems of particles with more mass concentrated at a greater distance from the axis of rotation have greater moments of inertia than bodies and systems of the same mass, but concentrated near the axis of rotation.