1. The problem statement, all variables and given/known data Beginning with Icm = Integral of r^2 dm from r1 to r2, find the moment of inertia of a solid sphere about any tangential axis. 2. Relevant equations Icm = Integral of r^2 dm 3. The attempt at a solution I set up the infinitesimally mass of an infinitesimally thin "shell" of the sphere: dm = 4ρπr2 dr And then solved for the moment of inertia: I = ∫r2dm = ∫r2(4ρπr2 dr) = 4ρπ∫r4 dr = (4/5)ρπr5 And solving for ρ we get the following: ρ = M/((4/3)πr3). Substituting that into the previously solved equation for I, I get the following: I = (3/5)Mr3. What am I doing wrong? I know the formula involves a coefficient of 2/5, not 3/5, but I can't find my problem. Thank you in advance!