Is it not inertia that makes a flywheel resist being put into motion? And if that is true, is inertia a consequence of being unable to create energy, i.e., why perpetual motion machines do not in fact work?
Clarification: I found the concept that a heavy object (heavy because it is on Earth but importantly weightless in outer space) would without gravity still resist motion -- as a youngster, I thought weightless would mean that you could push a huge object easily. But of course now I know that a massive object resists being moved in proportion to its mass. Perhaps others were puzzled in the same way at one point.
I also read of Mach's principle which, as I understand it, attributes this resistance to the effect of distant massive bodies -- the gravitational pull of objects even light years away.
What I am simply asking is, why this apparently almost mystical explanation? Would not a simpler explanation be, that if we push a massive object it now has momentum -- if it was a heavy flywheel and you got it moving, you could then run a generator. So since you can't create energy from nothing, it requires energy to get the flywheel to move and this is what we perceive as the resistance called inertia.