Trucks can be run on energy stored in a rotating flywheel, by an electric motor getting the flywheel up to its top speed of 200 rad/s. One such flywheel is a solid, uniform one cylinder with a mass of 500 kg and a radius of 1 m.
a) What is the kinetic energy of the flywheel after charging?
b) If the truck uses an average power of 8.0 kW, for how many minutes can it operate among charging?