1. The problem statement, all variables and given/known data I know this sounds silly, but I need to understand where I'm going wrong here. Prove the center of mass of a spherical rigid-body (solid sphere) is found at the origin explicitly, using spherical coordinates (zenith, etc.). 2. Relevant equations Centroid center of mass equation. 3. The attempt at a solution I originally tried using my own spherical coordinates, then found the conventional ones. However I'm not sure what the value of dV would be. For example, why wouldn't every infinitesimal dimension of dV be the square root of (dx+dy+dz)? thanks for reading this and any help you can offer.