# Will my fly wheel battery/generator break the law of energy conservation?

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I heard about fly wheel battery systems and after reading a bunch of articles and watching some videos about it I have an Idea. Basically the fly wheel looses it's rotational energy only due to friction(or am i wrong?), so if I we are able to eliminate all the friction forces by taking it to space where it won't take much energy to elevate it with magnets and also by creating vacuum, will I be able to create unlimited energy since the wheel will keep spinning for ever(or at least for drastically longer period than the current ones)?

Edited by A_curious_Homosapien
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"Will my fly wheel battery/generator break the law of energy conservation?"

No.

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41 minutes ago, A_curious_Homosapien said:

I heard about fly wheel battery systems and after reading a bunch of articles and watching some videos about it I have an Idea. Basically the fly wheel looses it's rotational energy only due to friction(or am i wrong?), so if I we are able to eliminate all the friction forces by taking it to space where it won't take much energy to elevate it with magnets and also by creating vacuum, will I be able to create unlimited energy since the wheel will keep spinning for ever(or at least for drastically longer period than the current ones)?

Even an ideal flywheel will lose energy if you take it away from it. So you won't get unlimited energy. And if you mean storing energy for an unlimited time, then a superconducting ring with a current or a vacuum capacitor is better.

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With zero friction a flywheel should keep spinning indefinitely - but when you draw any energy from it, eg by using it to power an electrical generator, it will slow down. You won't evade the laws of thermodynamics.

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You know that there is no such thing as 'frictionless', don't you ?

The laws of Thermodynamics can be likened to a card game ...

1 - You can't win ( can'tcreate energy in a closed system ).
2 - You can't break even ( no such thing as frictionless ).
3 - You can't get out of the game ( entropy )

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4 hours ago, A_curious_Homosapien said:

will I be able to create unlimited energy

A flywheel doesn't create any energy. It stores energy like a bucket stores water. Take energy from it, and the store decreases. Like a bucket, you could never get more out than what you put in. Keep taking energy, and it will slow and eventually stop.

Edited by mistermack
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12 hours ago, MigL said:

You know that there is no such thing as 'frictionless', don't you ?

Yes I do know but how, especially in this case? There so contact between the flywheel and literally anything that might cause friction, so how?

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46 minutes ago, A_curious_Homosapien said:

Yes I do know but how, especially in this case? There so contact between the flywheel and literally anything that might cause friction, so how?

Friction is a distraction here.

The basic point is @Ken Fabian's one, that any attempt to extract energy from the system will cause it to slow down and eventually stop. The energy you are trying to harness from the spinning flywheel is kinetic energy. If you remove kinetic energy from something, it slows down. The flywheel contains a finite amount of kinetic energy and that is the maximum energy you can obtain from it.

Edited by exchemist
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To build on exchemist's point.

Let's assume your flywheel is a magnet, and you've placed a coil nearby, but not touching it in any way. Essentially making a "frictionless" generator.

Your flywheel will continue to rotate unabated until you attach some type of load( say a light bulb) to the leads of your generator.

When you do this, current begins to flow through the wires including the coil.  This, in turn turns the coil into an electromagnetic, the polarity of which will apply an opposing force to the flywheel, slowing it down.  Keep the light hooked up long enough, and the wheel will stop spinning entirely.  Even there were no losses in the system, the total light energy produced by the bulb could only ever equal the total KE stored by the flywheel (which you would have had to have added to spin it up)

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In addition to what others have said, rotational energy can be lost frictionlessly in the same way the Earth loses rotational energy due to the presence of and interaction with the Moon (which has caused tidal locking over billions of years), the Sun, as well as other space objects of lesser influence.

Edited by Sensei
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2 hours ago, Sensei said:

In addition to what others have said, rotational energy can be lost frictionlessly in the same way the Earth loses rotational energy due to the presence of and interaction with the Moon (which has caused tidal locking over billions of years), the Sun, as well as other space objects of lesser influence.

That's rather interesting though, isn't it? Tidal interactions dissipate kinetic energy as heat. In some cases, e.g. ocean tides on Earth, that dissipation is due to friction. Though I suppose that tidal distortion of solid bodies is mainly not due to friction.

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On 11/24/2021 at 6:55 PM, A_curious_Homosapien said:

so if I we are able to eliminate all the friction forces by taking it to space where it won't take much energy to elevate it with magnets and also by creating vacuum

A couple of other points. you won't need to elevate it in space, and also, space isn't a perfect vacuum, so although tiny, there would be friction and it would eventually stop the flywheel.

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