A car is designed to get its energy from a rotating flywheel (solid disk) with a radius of 1.00 m and a mass of 600 kg. Before a trip, the flywheel is attached to an electric motor, which brings the flywheel's rotational speed up to 4,000 rev/min.
(a) Find the kinetic energy stored in the flywheel.
J
(b) If the flywheel is to supply energy to the car as a 20.0-hp motor would, find the length of time the car could run before the flywheel would have to be brought back up to speed.
h
2 answers
52584533.33joules
a) Use the formula E = (1/2) I w^2, where w is the angular speed in rad/s and I is the moment of inertia.
(b) Time = (Full speed energy)/Power
You will have to convert horsepower to Watts when using the formula
(b) Time = (Full speed energy)/Power
You will have to convert horsepower to Watts when using the formula