1. The problem statement, all variables and given/known data How do you find the tensor of inertia for fractions of the usual volumes? (like half of a sphere, half of a cylinder, half of a disk, quarter of a disk, etc.) I already know the tensor of inertia for the whole volume. Take M as the fraction of the volume's mass, not the whole volume's. 2. Relevant equations 3. The attempt at a solution I have no idea where to start... Thanks.