A small block of mass m lies above a thin disk of total mass M, constant surface density o, and radius R. A hole of radius R/2 is cut into the center of the disk, allowing the mass to pass though. The mass starts at a position along the central axis of the disk but is displaced a height Ah from the plane of the disk, where Ah < < R. There are no other external forces at work on this system; i.e., the disk and block are out in deep space. Assume m < < M. For the first order in Ah the block undergoes simple harmonic motion with respect to the centre of the plane of the disk, compute the period of oscillation of block. (A) (B) (C) (D) T= T = T = 2R Go TR Go TR 2Go None of these 4m Ah R/2 R M O