I have a mechanical engg. question that I could ask my dad but he's 7 hours ahead of me
Consider this zany contraption
Would it take less energy to drive the last gear underwater than it would above?
Can we construct a gearbox that arbitrages gravity?
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I see no reason it should. The inertia of the gear train would not change. You’d just add extra resistance. It should get marginally harder actually.
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ah damn...liquid resistance....
In principle tho if there were a gravity differential between the ends of the gearbox, are we doing something interesting or am I misunderstanding something other than basic laws of thermodynamics?
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Gravity is kinda irrelevant here. Inertia is rotational. I don’t see what you’re getting at tbh. Something like a space elevator arbitrages gravity in a way.
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I was assuming that it takes lesser energy to drive the last gear in that 65,000:1 gearbox
in a low gravity environment in order to drive the first gear
and
generate energy.
perpetual motion zanyness....
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Sorry no. Linear motion would be affected until equilibrium (a balloon underwater would float to surface) but not rotational.
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I see / Thank you.
Yeah i was under a false impression that 2nd law could be cheated by using energy generated by a 1:n gear ratio by operating the nth gear in 0 gravity.
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What's happening here?
Resistances ought not to make this possible, no?
Craft that's harvesting? wind energy into kinetic but also geared to push itself ahead of the wind....?
youtu.be/jyQwgBAaBag
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Dunno. Would have to do the vector math. The prop is acting like 2 tacking sails canceling out lateral forces I think. It shouldn’t be compared to pure downwind like a spinnaker.
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And remember velocity is not energy. E- 0.5mv^2. The m matters. A large decelerating mass of air can accelerate the craft with less mass to less than energy lost but with higher velocity. Like falling ball accelerates while losing energy net (so it bounces less high next bounce)

