physics
posted by mike on .
A car is designed to get its energy from a rotating flywheel with a radius of 1.50 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 4000 rev/min.
(a) Find the kinetic energy stored in the flywheel.
(b) If the flywheel is to supply energy to the car as would a 15.0 hp motor, find the length of time the car could run before the flywheel would have to be brought back up to speed.

I think for a i might have the wrong answer it seems really large. first i converted the revs/min to rad/s and got 418.88 rad/s. is this were i am wrong. also what is its moment of inertia.