Flywheels are large, massive wheels used to store energy. They can be spun up slowly, and then the wheel's energy can be released quickly to accomplish a task that demands high power. An industrial flywheel has a 1.5 meter diameter and a mass of 250 kilogram. Its maximum angular velocity is 1200 rpm.
A motor spins up the flywheel with a constant torque of 50 N x m. Find how long does it take the flywheel to reach top speed?