One way to store energy is in the rotational motion of a flywheel, and some have proposed using such technology to power automobiles. One unit is based on a 7.0-kg flywheel in the shape of a hoop of radius 0.11 m that spins as fast as 50000 rpm.a. How much kinetic energy is stored by the flywheel when it is rotating at its maximum rate?b. If the vehicle requires an average power of 11 kW under normal driving conditions, for how much time can it operate with the energy stored in the flywheel?