4 ms·

> And because it does not require energy just to hold things up (just as a chair does not require power to keep you off the ground), in theory you could have a

> And because it does not require energy just to hold things up (just as a chair does not require power to keep you off the ground), in theory you could have a hoverboard which does not require energy to float in the air. An item where you could dump electricity into it once, cut power, and have it resist gravity -- forever, and for free! -- is absolute horse shit.

FiatLuxDave 12y ago
>An item where you could dump electricity into it once, cut power, and have it resist gravity -- forever, and for free! -- is absolute horse shit. Um, you are completely wrong. There is a difference between force and energy. It is certainly possible to expend a small amount of energy to create a force which lasts in perpetuity. Energy = Force x Distance, and if there is no displacement in distance, then no energy is spent by the exertion of a force. Not to say that making hoverboards and flying cars is an easy engineering proposition, but that is due to the parameters of the problem, not due to any intrinsic issue with the physics of providing a force against gravity. If people weighed a nanogram, or the Earth's magnetic field were 1 Tesla, or the electrostatic potential between the stratosphere and the Earth was 100,000 times stronger... any one of these and we'd have had hoverboards a long time ago. But that's just numbers. There is no problem with spending a finite amount of energy to create a perpetual force.
- fatmanscoop 12y ago
  Even using Energy = Force X Distance you need to overcome the force of gravity been exerted upon the object, this means you need to continually exert a positive for force to overcome this.
chopin 12y ago
Any superconductor levitating on a magnet does exactly this. Afaik there is no law in physics we know of which forbids this. To put it even further: every stone lying on the ground does exactly this. It doesn't change its position relative to the gavitational field. And without expending any energy for that (or increasing the systems entropy ot hold its position). And this comes ultimately down to electromagnetic forces (between valence electrons) holding it at its position. So, no horse shit here.
- MiguelHudnandez 12y ago
  A stone resting on the ground is simply halted at the place where gravity is overpowered by the repulsion between molecules. Both of those forces are applied constantly, and seemingly for "free." But those forces are inherent to all matter. Two magnetic objects can resist each other, but that is well understood already. And still, those reach equilibrium between gravity (from the levitator) and the strong force (from the support structure). From the way I understand superconductive magnetic levitation, the magnetic field collapses the superconductivity in the places they intersect. That would mean that over time, electrical resistance would drain the [mostly] superconductive material. Right now, all examples of superconductive levitation involve supercooled superconductors, which means that any examples require massive amounts of energy to sustain. This hoverboard idea would be like taking the magnetic base away and expecting the levitator to remain where it is with no extra energy supplied. We've gone from "we can turn energy into motive force through unknown methods" to "we can prime this thing with energy once and have it exert force forever." If that were true, you could dump 1kw into the thing, rotate it 90 degrees and attach it to a rotor. Now you've got this thing that constantly pushes your rotor around and you've got free energy forever. See how I might think we're in crazy town now?
- XorNot 12y ago
  Any regular magnet stuck to a fridge is doing this too. Which is very much where a lot of the misunderstandings of people with free energy seem to stem from: they fail to recognize magnetism as no different to the force which is stopping the fridge, the floor and everything else from simply plummeting through the Earth.

FiatLuxDave 12y ago

>An item where you could dump electricity into it once, cut power, and have it resist gravity -- forever, and for free! -- is absolute horse shit. Um, you are completely wrong. There is a difference between force and energy. It is certainly possible to expend a small amount of energy to create a force which lasts in perpetuity. Energy = Force x Distance, and if there is no displacement in distance, then no energy is spent by the exertion of a force. Not to say that making hoverboards and flying cars is an easy engineering proposition, but that is due to the parameters of the problem, not due to any intrinsic issue with the physics of providing a force against gravity. If people weighed a nanogram, or the Earth's magnetic field were 1 Tesla, or the electrostatic potential between the stratosphere and the Earth was 100,000 times stronger... any one of these and we'd have had hoverboards a long time ago. But that's just numbers. There is no problem with spending a finite amount of energy to create a perpetual force.

fatmanscoop 12y ago
Even using Energy = Force X Distance you need to overcome the force of gravity been exerted upon the object, this means you need to continually exert a positive for force to overcome this.

chopin 12y ago

Any superconductor levitating on a magnet does exactly this. Afaik there is no law in physics we know of which forbids this. To put it even further: every stone lying on the ground does exactly this. It doesn't change its position relative to the gavitational field. And without expending any energy for that (or increasing the systems entropy ot hold its position). And this comes ultimately down to electromagnetic forces (between valence electrons) holding it at its position. So, no horse shit here.

MiguelHudnandez 12y ago
A stone resting on the ground is simply halted at the place where gravity is overpowered by the repulsion between molecules. Both of those forces are applied constantly, and seemingly for "free." But those forces are inherent to all matter. Two magnetic objects can resist each other, but that is well understood already. And still, those reach equilibrium between gravity (from the levitator) and the strong force (from the support structure). From the way I understand superconductive magnetic levitation, the magnetic field collapses the superconductivity in the places they intersect. That would mean that over time, electrical resistance would drain the [mostly] superconductive material. Right now, all examples of superconductive levitation involve supercooled superconductors, which means that any examples require massive amounts of energy to sustain. This hoverboard idea would be like taking the magnetic base away and expecting the levitator to remain where it is with no extra energy supplied. We've gone from "we can turn energy into motive force through unknown methods" to "we can prime this thing with energy once and have it exert force forever." If that were true, you could dump 1kw into the thing, rotate it 90 degrees and attach it to a rotor. Now you've got this thing that constantly pushes your rotor around and you've got free energy forever. See how I might think we're in crazy town now?
XorNot 12y ago
Any regular magnet stuck to a fridge is doing this too. Which is very much where a lot of the misunderstandings of people with free energy seem to stem from: they fail to recognize magnetism as no different to the force which is stopping the fridge, the floor and everything else from simply plummeting through the Earth.