1. The problem statement, all variables and given/known data The moment of inertia of a uniform sphere of mass m and radius r about an axis passing through its center of mass is (2/5) mr^2. If half of the sphere is removed, what is the moment of inertia about the same axis? 2. Relevant equations integral of r^2 dm 3. The attempt at a solution http://img407.imageshack.us/img407/5250/mech221ps4moiim8.jpg [Broken] I think this is wrong since I've looked up the actual I for this and it gives me (2/5) mr^2 still. I also tried using the parallel axis theorem on this and it also gives me the (2/5) mr^2. What am I doing wrong?