Please Answer in Full A flywheel is a solid disk that rotates about an axis that
ID: 1399557 • Letter: P
Question
Please Answer in Full
A flywheel is a solid disk that rotates about an axis that is perpendicular to the disk at its center. Rotating flywheels provide a means for storing energy in the form of rotational kinetic energy and are being considered as a possible alternative to batteries in electric cars. The gasoline burned in a 331-mile trip in a typical midsize car produces about 2.46 x 109 J of energy. How fast would a 7.63-kg flywheel with a radius of 0.480 m have to rotate to store this much energy? Give your answer in rev/min.
Explanation / Answer
Moment of inertia of fly wheel, I = 0.5*M*R^2
= 0.5*7.63*0.48^2
= 0.879 kg.m^2
we know, KE = 0.5*I*w^2
==> w = sqrt(2*KE/I)
= sqrt(2*2.46*10^9/0.879)
= 74815 rad/s
= 74815*60/(2*pi)
= 714430 rev/min