Rotational Motion Of Flywheels

Description
A car goes down the hill and loses a lot of gravitational p.e. Can this energy be stored as rotational k.e of a flywheel and used for taking the car up the hill without using any fuel in the upward journey? This is just a hypothetical question at this stage but throws us in a thinking mode. Indeed the rotational k.e is being used to generate strong magnetic fields in laboratories of MIT as shown in this lecture <br/><br/>Prof. Walter Lewin, 8.01 Physics I: Classical Mechanics, Massachusetts Institute of Technology: MIT OpenCourseWare), http://ocw.mit.edu (Accessed June 13, 2011). License: Creative Commons BY-NC-SA: http://ocw.mit.edu/terms/#cc