Perpetual Motion and why it is not possible

[Pebbls]

Perpetual Motion and why its not possible,

Perpetual motion: the motion of a hypothetical machine that, once activated, would run forever unless subject to an external force or to wear.produces work without the input of energy, a machine which spontaneously converts thermal energy into mechanical work

Examples of perpetual motion devices: an electric car that charges itself when it drives, A clock that winds itself as tells time.

Why isn't it possible? These thing are governed by the first two laws of thermodynamics.

The first law of thermodynamics: ∆U = q+w, ∆(delta)U The change internal energy of the system, and (q)The heat transferred into/out of the system and (w) The work done by/on the system. ΔU=q+w

simply states that energy can be neither created nor destroyed (conservation of energy). Thus power generation processes and energy sources actually involve conversion of energy from one form to another, rather than creation of energy from nothing.

Example of the first law:

Battery=chemical energy to electrical

Photosynthesis= Optical energy to Chemical energy

The Second law of thermos dynamics:  dS=∂Q/T The infinitesimal change in entropy of a system (dS) is calculated by measuring how much heat has entered a closed system (∂Q) divided by the common temperature (T) at the point where the heat transfer took place.

The Second Law of Thermodynamics is commonly known as the Law of Increased Entropy. While quantity remains the same (First Law), the quality of matter/energy deteriorates gradually over time. HuH? Usable energy is inevitably used for productivity, growth and repair. In the process, usable energy is converted into unusable energy. Thus, usable energy is irretrievably lost in the form of unusable energy.

 

With this information you can see why perpetual motion is not an option. There is a bit more to this due do the three categories of "Perpetual devices." Here are some perpetual device images to give you an idea.

Edited September 11, 2014 by Snorkel

[Vanaraud]

Not arguing the laws of thermodynamics but magnets are buffling to me also. On this pic the forces are balanced and it won´t work but where does the magnets take their energy? I mean if you´d take material with permanent magnetic properties and say put it pulling or pushing some objects it doesn´t "wear out"? neither do the spins stop? If we´d figure out how to harnest this "indefinete energy" would it there be changes in some distance place in dark matters enthropy?

[Pebbls]

Not arguing the laws of thermodynamics but magnets are buffling to me also. On this pic the forces are balanced and it won´t work but where does the magnets take their energy? I mean if you´d take material with permanent magnetic properties and say put it pulling or pushing some objects it doesn´t "wear out"? neither do the spins stop? If we´d figure out how to harnest this "indefinete energy" would it there be changes in some distance place in dark matters enthropy

 A permanent magnet needs just as much force to pull away than it gives out when attracting, so no perpetual motion. Even if there was no friction—and inevitable energy loss—the magnets will lose its magnetism after a few years. If we some how or some way found an "infinite energy source" we would eventually find that is converting one energy to another so it would taking away from something and eventually run out of what ever its using for energy. There are technically perpetually moving things in a vacuum but these do not create energy and can not produce energy but will store energy.  Say you have a dam with water above it and you want to harness its gravitational potential energy by using turbines or water wheels. eventually you would have no more water at the top. It would cost energy to get the water back to the top therefore no perpetual motion machine. Same thing would apply to magnets

Suppose you have gravitational potential energy in some form you can harness, like water above a dam. You can let the water down and extract some energy (using turbines or waterwheels or whatever you like), but when you're done, the water is below the dam. To repeat this cycle you would have to spend energy to raise the water back up again, storing gravitational potential energy once again.

 

The same idea would apply for magnets.

 

Lots of cool stuff here: http://www.physicsforums.com

Edited September 11, 2014 by Snorkel

[Vanaraud]

Yes, I was wondering if there are any experiments made to see if magnets "wear out" as personally I´ve seen no magnet wearing out. Take for instance magnets on wardroabs?

Also the net is full of magnetic motors supposedly "running forever", though I´m scepticalt as why it hasn´t gone to mass production yet and there are not any explanations given of how they work.

And what about magnets, there is this theory that magnets are made of particles aligned similarly called "spins", for example electrons spinning around nucleos of atom, but what keeps electrons spinning around? Do they "wear" out also? This leads us to the "Big Bang" theory which is questioned lately a lot also and even if the "Big Bang" theory holds then the "ending" of universe is still unanswered, which leads me to the question where did the energy come and go eventually. Or in the other way put if energy is created and then vanished with universe collapsing. Or even if it collapses if it leads to new "Big bang" and the energy transformation goes on.

Also gravitons haven´t been discovered to my knowledge yet, if discovered could? put that "hydro dam experiment" under question mark also.

But yep with current theories in physics backed up with experiments the laws of thermodynamics hold. Till somebody makes enough experiments to prove it wrong.

For everyday life it would help to save huge amounts of energy just by making production and distribution of electricity more efficient.

[RedBaird]

Snorkel, I love your illustrations!  Don't forget this one.  

 

[RedBaird]

What?  Double Post?