Posted by Anonymous on Wednesday, March 17, 2010 at 4:18pm.
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.

Physics Rotaional Kinetic Energy  bobpursley, Wednesday, March 17, 2010 at 4:24pm
Model the flywheel as a sold disk, look up the moment of inertial
KE= 1/2 I w^2 where w=4000^2PI/60 rad/sec
change 15hp to kwatts
time= power/KEabove 
Physics Rotaional Kinetic Energy  Anonymous, Wednesday, March 17, 2010 at 5:22pm
Can i have more help i tried that every time in part a and get the wrong answer on my webassign i tried it 5 times and got five different answers. the answer would be nice so i can get part b.