1. The problem statement, all variables and given/known data A sphere (radius = 0.60cm) can be rotated about an axis through its center by a torque of 25 N*m, which accelerates it uniformly from rest through a total angular displacement of 180 rev in a time of 15 s. What is the mass of the sphere? 2. Relevant equations My text book says that this is the formula for the [solid] sphere: I=(2/5)MR^2 3. The attempt at a solution Well, I don't really know what to do here, but I tried this: I=(2/5)MR^2 I = M* (2/5)(.60)^2 I = .144 m. However, that doesn't make a lot of sense; I'm pretty sure there has to be another equation that needs to be used. I need someone to explain this to me and guide me through this process. Thank you.