Perpetual motion describes "Motion that continues indefinitely without any external source of energy; impossible in practice because of friction." It can also be described as "the motion of a hypothetical machine which, once activated, would run forever unless subject to an external force or to wear"...

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Why can't rotating magnets in space or zero gravity be used to create infinite energy? [on hold]

I would like to know if a system like the one below will possibly work. I understand that the laws of physics forbid the "creation" of energy but despite my efforts I haven't been able to figure out ...
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Vertical Motion Question [on hold]

Question: An object is projected vertically to to the ground in a 20 m/s velocity. After 3 seconds another object is projected from the same position in the same velocity to the same direction. ...
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2answers
259 views

What's wrong with this idea for recover energy from pressure?

In this case : It's a theoretical study, just for find my error. No gravity. No buoyancy. All volumes are constant. I suppose no friction. Outside the pressure from air is constant at $P$ (atmospheric ...
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1answer
144 views

Why this is not a perpetuum mobile [duplicate]

If we imagine a device like one shown on the picture above, why can't we say that it would work? Here is a cylinder somehow placed in the fluid by one of his sides (one in the box). Due to additional ...
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25 views

Could an infinite spinning windmill create endless electricity? [closed]

This is not so much a question about if this idea is physically possibly, but more a question of if it was possible. If a magnet could somehow push a windmill around at a constant speed continuously, ...
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Long life energy usage

I'm doing a project at school. I want to re-use energy. I know that it will not run forever (but I hope it will run very long). So I wanted to ask if the image below is right and I could use it at ...
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1answer
35 views

Feynman's argument on machine limits: how are the machines reset?

Feynman makes an argument in his Lectures that loses me on one point. His argument (abbreviated): We suppose that there is a reversible machine—which lowers one unit of weight by one unit of ...
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35 views

Does a degassed magnet weigh less than one that is not?

I learned matter with an electric current weighs more than matter with no current. Does that apply to magnetic material in the same way but with it's magnetic fields instead of electric current? A ...
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1answer
42 views

“Nearest” Perpetuum Mobile? [closed]

We all know the concept behind Perpetuum Mobile. Instead of trying to grasp the impossible, how near could we actually approach the general idea? By this I mean to look at the "apparent perpetual ...
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66 views

Can Gravity be used as an energy source?

Let's say there is a planet that is in the middle of nowhere so it isn't moving all the time like a planet in a solar system. The pressure caused by gravity pulling down towards the centre of mass (...
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2answers
96 views

If I spinned a fan in a vacuum it will keep spinning forever. Why can we not make energy out of it? [duplicate]

Suppose we created a vacuum and spinned a turbine inside it with some amount of force. According to newton's second law it will keep spinning as there is no air resistance, so why can we not make ...
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1answer
219 views

Energy Conservation in Kinetic Power Plants [duplicate]

Quite recently the company Rosch has developed a new kind of power plant that supposedly utilizes the buoyancy effect to generate electricity. The apparatus consists of a vertical conveyor belt with ...
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1answer
229 views

What prevents this magnetic perpetual motion device from working? [closed]

Two days ago, I thought of this device, which may seem to rotate indefinitely(in all 3 directions). I have two questions. Is this perpetual motion machine already known? If it is, could you please ...
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Understanding Feynman's argument about Stevinus

In the Feynman lectures vol 1, chapter 4, he mentioned a "Brilliant, clever" way of solving a problem named: A simple example is a smooth inclined plane which is, happily, a three-four-five ...
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2answers
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Why does the “Troll-Mobile” not work?

See image: If I'm not totally dumb the car would move when the right magnet would not be attached to the car, at same distance of the booth magnets. So why would it not move?
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2answers
674 views

Why does this capillary action generator not work?

So I was doing a bit of reading. Apparently the the obstacle to generating energy from the forces driving capillary action is breaking the surface tension at the top of a capillary tube. It is just ...
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2answers
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Perpetual motion machine [duplicate]

I'm having trouble understanding why this machine doesn't work. Part of a ring, half of which is uniformly charged, is located between two oppositely charged plates, attracting to the negative one and ...
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1answer
326 views

Perpetual motion machine with magnets [duplicate]

I have been recently made aware of the following motor, which uses two magnets and a wheel to generate motion, and the creator of this machine claims that this motion is perpetual. Here is a ...
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1answer
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Is Hydroelectric power plant a perpetual motion machine? [closed]

Is Hydroelectric power plant a perpetual motion machine of second kind from this classification https://en.wikipedia.org/wiki/Perpetual_motion#Classification ??? or not? If not which kind of ...
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Generating unlimited electricity through magnets

Well i had seen a toy, which i till date don't know was it battery powered or not? and also could it be used to actually create energy (I know that it is not possible but whats the problem?) ...
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653 views

Picturing Feynman's argument about perpetual motion

So, there is a certain paragraph in Fenyman's book that I'm struggling with for quite some time. It says: We imagine that there are two classes of machines, those that are not reversible, which ...
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1answer
105 views

Why won't this Casimir effect perpetual motion machine work?

So the Casimir effect is caused by an imbalance in radiation pressure(caused by virtual particles) on two sides of a metal plate. This is typically shown with two close plates getting pushed towards ...
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5answers
82 views

Extract energy from the atmosphere? [closed]

Let's say we would fill a long tube with water. Let's say the tube is 1km in height. At the bottom of this tube, the pressure should be much higher than the top. Also, the tube would lead into a ...
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3answers
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Why can't I do this to get infinite energy?

I know that I cannot do this because of conservation of energy, so I am looking for an answer as to why this will not work. So by my understanding of Einstein's whole famous $E=mc^2$ thing it is ...
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3answers
353 views

What is the secret of this perpetual motion machine with neodimimum magnets?

The following device is apparently based on magnetic forces only and has no visible energy source: Where is it's energy source? Full video: http://www.youtube.com/watch?v=eA0b-8pqUCk UPDATE One ...
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3answers
535 views

A potential perpetual motion machine?

If I were to freeze a superconductor, the ones made up of yttrium barium copper oxide, with liquid nitrogen and placed it on one of those strong neodymium magnets, it should float right? Now what ...
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Will spinning DC motor in space generate infinite energy?

If I take a DC motor far in space and spin it, will it continue to spin forever and generate infinite electrical energy? If so, then won't it violate law of conservation of energy?
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Is it a law of physics that all machines will break?

The question sounds kinda dumb when I say it out loud but at the same time I'm very curious. When things break, is it solely due to an intrinsic design flaw or is it due to entropy? And is the ...
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1answer
125 views

Why is it so hard to explain that the Brownian Ratchet doesn't work?

The Brownian Ratchet stood up to a lot of scrutiny before it was finally shown why it would not work as a perpetual motion machine, but it seems weird to me that all of that was necessary. If the ...
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1answer
63 views

Can u explain below diagram is possible or not [closed]

If I takes 3 balloons with same size they r connected with same thred frist end have 2 balloons and second end have 1 balloon I put same manner as shown in diagram then frist end is gos up or not or ...
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1answer
112 views

I m just try to make Free energy using buoyancy [duplicate]

Can I make power (electricity ) using buoyancy see diagram. if this diagram is possible then how much power i get . I just need formula for upwards speed.
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3answers
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Is magnetic wheel possible?

I once tried to make a magnetic wheel using different shaped magnets and placing them in different orientations and of different shapes.But it did rotate making a small angle ie it didnt rotate even a ...
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Disregarding the claim of perpetual motion. Does this design have any merit at all?

I'm wondering, in reference to this youtube video Whether or not this design would actually make the wheel move. Any big brains out there wanting to help me out would be greatly appreciated
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How does the second law of thermodynamics forbid the possibility of perpetual machine of the second kind?

Fermi in his lecture asserts: The second law of thermodynamics rules out the possibility of constructing a perpetuum mobile of the second kind. So, this means there can be no machine which just ...
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193 views

Do Magnets ever lose their magnetism, and if so how long does it take? [duplicate]

I was talking with a friend about a design for a perpetual motion machine that used magnets, but he said that magnets eventually lose their magnetism. I don't want anyone to go into how Thermodynamics ...
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6answers
685 views

Extracting heat energy without a heat engine

Is it possible to extract the molecular kinetic energy from a system directly (without the use of a heat engine / temperature gradient) and convert that to another form of energy, such as electricity, ...
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80 views

Pseudo-Perpetual Motion Machine

Clearly, the Second Law of Thermodynamics precludes the existence of any theoretical device that would continue running throughout the lifetime of the universe. However, is it possible to construct a ...
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Particles radiating energy when accelerating?

Let us say we have a charged particle moving in the positive $X$ direction with velocity $v$. If we give the particle a nudge in the $-X$ direction causing it to decelerate. Then from the saying '...
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Perpetual motion machine of the second kind possible in nano technology?

First of all sorry for my English - it is not my native language. During my engineering studies at the university the thermodynamics professor told us that the "second law of thermodynamics is not ...
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1answer
339 views

Why can't it work? Perpetual motion machine [duplicate]

Lets assume that the red ball is more dense than the white fluid and less dense than the blue fluid. The fluids are of very low viscosity and the machine can be of any height. The flaps open when ...
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1answer
70 views

Is a convergent-divergent nozzle a perpetual motion machine of the second kind?

As answered in this question, a convergent-divergent nozzle (de Laval nozzle) accelerates a gas flow by converting its heat energy into kinetic energy. My intuition says that this violates the second ...
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Was the impossibility of the second degree perpetuum mobile in the General Relativity ever proven?

Somewhere I've heard, that gravity often likes to work against the entropy. For example, the surprisingly low temperature of the black holes. Or see the gravitational separation of different elements ...
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1answer
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Perpetual Mobile and Gravitation

I have fundamental question about what is called the “law of conservation of energy”. We all hear about the tidal power stations which using the tidal power. The source of the tidal power came from ...
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5answers
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Why doesn't this magnetic perpetual motion machine work?

I know that this machine does not work, via thermodynamics. I am asking for an analysis in terms of mechanics and magnetism. Anyway, so here is the machine: The magnet (the red ball) pull the ball ...
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1answer
365 views

How does this capillary-action setup not become a perpetual motion machine?

If you have a very thin glass tube and you place it into water, let's say the water in the tube rises to the height of $x$ mm from the surface of the water. What would happen if you poked a hole in ...
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2answers
1k views

How to understand Feynman's reasoning about perpetual motion?

I'm studying Feynman's Lectures on Physics, and I'm not really understanding his reasoning here: Consider weight-lifting machines $\overline{}$ machines which have the property that they lift one ...
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1answer
162 views

NOT Perpetual Motion; Could It Work?

TL;DR The energy is not being created freely, so why shouldn't it work? We have all seen the YouTube "perpetual motion" machines. You know, the computer fans with magnets taped on them and hidden 9 ...
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148 views

Why is this not considered a perpetual motion machine?

You have to assume some wacky things for this scenario, but nothing that defies physics as far as I can tell. I'm going to describe this with a human being initially, because I think it makes the ...
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What physical conditions would allow for this kind of perpetual seesaw

I'm working with a simulator(Box2D) and need to create these conditions. I have a perpetual seesaw with two objects on either side. I'd like for the following conditions to be met. The first ...