Flywheels are large, massive wheels used to store energy. They can be spun up slowly, then the wheel's energy can be released quickly to accomplish a task that demands high power. An industrial flywheel has a 1.5 m diameter and a mass of 450 kg. Its maximum angular velocity is 1150 rpm.
(a) A motor spins up the flywheel with a constant torque of 60 N · m. How long does it take the flywheel to reach top speed?
s
(b) How much energy is stored in the flywheel?
J
(c) The flywheel is disconnected from the motor and connected to a machine to which it will deliver energy. Half the energy stored in the flywheel is delivered in 2 seconds. What is the average power delivered to the machine?
kW
(d) How much torque does the flywheel exert on the machine?