Question

as seen in the lecture 19 of mit ocw, physics, the professor mentions the use of flywheels to store gravitational PE nd use to slow down the car going down a mountain by converting it into rotaional kinetic energy of the disk. my question is that if we were to put dis to practical use, there would be enough viscous drag due to the atmosphere to produce great amount of heat energy when the flywheel rotates at such a high speed. how would this in any way reduce the heat energy produced, which, by the way, is one of our prime objectives?

Answer 1

I knowthe way you are imagining this to be. The flywheel is not as open towards the base of the car, As a slight bump the the base and the disk may be affected. It is well packed between Insulations and lubricants. IT HAS COME TO PRACICAL USE TOO.