1. The problem statement, all variables and given/known data The moment of inertia of the disk-clay system about the central axis of the disk is I = 1.5 kg m2 Disk's mass = M The clay's mass = 0.12 kg Calculate the mass of the disk? 2. Relevant equations I = m r^2 3. The attempt at a solution I thought that the moment of inertia may just be the sum of the individual moment of inertia's of the two objects. I know that I for a disk is equal to 1/4 MR^2, but I do not know the one for the clay.