Question

Please identify the physical principles and assumptions that you need to apply in order to solve the problem. Outline the steps needed to solve the problem including all mathematical calculations you will need to make.

One suggestion for storing energy generated by solar and wind energy created during off-peak hours is to store it as mechanical energy. One method would be to manufacture large flywheels that spin on nearly frictionless bearings. Consider a flywheel made of iron (density of 7.8 g/cm3) in the shape of a uniform disk with thickness of 10 cm.

a.) What would the diameter of the flywheel be if it was designed to store 10 MJ of kinetic energy while spinning at 90 rpm about an axis perpendicular to the center of the disk?

b.) What would be the centripetal acceleration of a point on the rim of the disk when spinning at this rate.

Answer 1