A 13-cm-diameter cd has a mass of 25 g. part a what is the cd's moment of inertia for rotation about a perpendicular axis through its center?

Answer: For a disc, the moment of inertia about the perpendicular axis through the center is given by 0.5MR^2. where M is the mass of the disc and R is the radius of the disc. For the axis through the edge, use parallel axis theorem. I = I (axis through center of mass) + M (distance between the axes) ^2 = 0.5MR^2 + MR^2 (since the axis through center of mass is the axis through the center) = 1.5 MR^2