A 10.7kg cylinder rolls without slipping on a rough surface. At the instant when its center of gravity has a speed of 11.8 m/s, a) Find the translational kinetic energy of its center of gravity. b) Find the rotational kinetic energy about its center of mass at that time. c) What is its kinetic energy? I already found the answer to a by using the formula Ke = .5mv^2 and it's 744.934 J. For b I want to use the rotational kinetic energy formula Ke = .5Iω^2, but I need inertia for that. I can't find the inertia without the radius. Besides, I wouldn't know what formula to use since they don't explicitly say whether or not the cylinder is hollow.