Before electric hybrid cars, one way that had been suggested for storing the braking energy is to store it in the ke of a spinning mass. the moment of inertia for a hollow cylinder has an inner radius of 7/8 of the otter radius is .9mr^2, where m is the mass of the cylinder and r is simply the radius.
a. what angular velocity in radians per second would be needed to in the spinning cylinder of iron with a mass of 60kg, radius of .20m to store 200,000 joules of energy? what is this in revolutions per minute?
b. torque needed to be applied to the cylinder by the coupling mechanism if 2 joules from above were to be achieved in 1 second at constant acceleration?
c. what would we need to do if we wanted to reduce the weight of the hollow cylinder and keep the energy storage? what is one engineering problem that would need to be addressed on strain limits of materials and forces in rotation objects?