Rolling sphere, problems with the fundementals. 1. The problem statement, all variables and given/known data A sphere with the mass of 2.5 kg rolls without slipping. The speed of the center of gravity is 10 m/s. a) Calculate the translational kinetic energy of the sphere b) Calculate the rotational energy of the sphere c) Calculate the total kinetic energy of the sphere d) Repeat a)-c) for a hollow cylinder with the same mass and speed 2. Relevant equations vT = ω x r ,where vT is the speed of the center of gravity for the sphere Er = 1/2 x I x ω^2 , where Er is the rotational energy and ω=angular velocity I = 2/5 x M x r^2 , moment of inertia of the ball Ek = 1/2 x m x vT^2 + 1/2 x I x ω^2 , where Ek is the total kinetic energy of the rolling motion 3. The attempt at a solution My first thought was finding the radius using vT=ω x r , my book says that ω=2 rad/s r = (10 m/s)/(2 rad/s) = 10/2pi m, but im really not sure if im allowed to do this. I can't find any examples in my textbook that relates to this problem.