I assumed that the belt goes from north pole to north pole (south pole to south pole) and thus the length of belt that gets accounted for being in contact with the pulleys would be half of the sum of the circumferences of the pulleys. I do not know enough about pulleys to know if and how to...
Well, I do not know specifics about pulleys so some of my math or assumptions might be wrong, but here goes nothing.
Assume we have pulleys with radii R,r respectively such that R>r.
Assume we have a belt with radius p, thus length P= 2p\pi.
Let c be the distance from the tops(bottoms) of...