My boss and i were considering he following problem (see attached image): 2 unequal masses rotate an equal distance, r, about an axis. We both agreed that regardless of their angular position from eachother (wether they were diametrically opposed or otherwise oriented, the 2 examples shown in the image) is not relevent to their moment of inertia. However, you should be able to calculate the MOI using their center of mass and its distance, x, from the rotation axis. There is obviously something wrong with this assumption, since r and x are not equal. Can someone shed some light on this? Also, I am ignoring their centroidal mass moments.