JeffDG
Touchdown! Greaser!
How is any of that "almost perpetual"? There is a constant input of energy and the output of energy is less than the input due to losses in things like friction which contrary to your previous statements ARE definable and calculable.
Well, technically, the input of energy equals the output of energy. The amount of useful work is less than the input energy, the remainder is wasted in frictional heating and other such mechanisms.