One possibility for a low-pollution automobile is for it to useenergy stored in a heavy rotating flywheel. Suppose such a car hasa total mass of 1100 kg, uses a uniform cylindrical flywheel ofdiameter 1.50 m and mass 240 kg, and should be able to travel 350km without needing a flywheel �spinup.� (a) Make reasonableassumptions (average frictional retarding force = 450 N, twentyacceleration period from rest to 95 km/h, equal uphill anddownhill, and that energy can be put back into the flywheel as thecar goes downhill), and estimate what total energy needs to bestored in the flywheel. (b) What is the angular velocity of theflywheel when it has full �energy charge�? (c) About how long wouldit take a 150 hp motor to give the flywheel a full energy chargebefore a trip?
