A fly-wheel is a solid disk which rotates around an axis which is perpendicular to the disk at its center. Rotating flywheels give a means for storing energy in the form of rotational kinetic energy and are being considered as the possible alternative to batteries in electric cars. The gasoline burned in a 340 mile trip in a typical midsize car generates around 1.60 x 109 J of energy. Determine how fast would a 15 kg fly-wheel having a radius of 0.22 m have to rotate to store this much energy? Represent your answer in rev/min.