A massless string is wrapped around a solid disk of mass m_1 and tied to a block of mass m_2. The disk is free to rotate on a frictionless horizontal axle. This picture is now copied exactly except that the disk is replaced with a bicycle wheel (of mass m_1, of course) with an identical radius. A wheel differs from a disk in that essentially all of the mass is on the rim. If the two blocks are now released from rest simultaneously from the same height, which one will hit the ground first?