Question

In the design of a passenger bus, it is proposed to derive the motive power from the energy stored in a flywheel. The flywheel, which has a moment of inertia of 4.0 x 10^2 kgm^2, is accelerated to its maximum rate of rotation 3.0 x 10^3 revolutions per minute by electric motors at stations along the bus route. (i) calculate the maximum kinetic energy which can be stored in the flywheel. (ii) if, at an average speed of 36 kilometres per hour, the power required by the bus is 20 kW, what will be the maximum possible distance between stations on the level?