1. The problem statement, all variables and given/known data A large disk of mass M and radius R is spinning like a CD of merry-go-round - that is, about an axis perpendicular to the plane of the disk. It is rotating at an angular velocity (omega initial). At some instant, a sphere of mass M/4 , which is initially not rotating, is dropped onto the disk at a distance of 3R/ 4 from the center. The sphere sticks to the disk and begins rotating with it. Find the final velocity of the disk-sphere combination. 2. Relevant equations solid cylinder = I = 1/2 mr squared solid sphere - I = 2/5 mr squared (not sure if these are the correct inertia formulas) 3. The attempt at a solution i have no idea...i don't even know how to start the problem....should i find inertia of disk first?