Problem: An experimental flywheel, used to store energy and replace an automobile engine, is a solid disk of mass 200.0 kg and radius 0.40 m. (a) What is it's rotational inertia? (my calculation says 16 kg.m) (b) When driving at 22.4 m/s (50 mph), the fully energized flywheel is rotating at an angular speed of 3160 rads/s. What is the initial rotational kinetic energy of the flywheel? My thinking was to find the KE (rotational) = 1/2 I w^2 but the number is huge. 1/2 (16)(3160). Am I on the right track? Thank you.