Magnets to create Perpetual Motions Machines, Why is it Impossible?

[Deleted]

I only have a 12th grade level of physics education so keep that in mind. I was thinking about how energy cannot be created, and how magnets seem to break this rule.

If a bigger magnet pulls a metal object, it has done work on the object. But did the big magnet "lose" some of its magnetic power? No, right? So doesn't that mean magnets can do work forever (or until they wear out, if they do)?

Anyone who's a physics nut care to explain why we haven't gotten something like this invented yet? Using magnets to spin something would create friction in some way or another, but if the only loss of energy is through friction would it mean tis pretty damn efficient? And for all intents and and purposes is a very good machine for making energy?

I guess the problem is keeping the metal object from reaching the magnet, since then the "energy" will stop?

 

[BrailleOperatic]

The problem with your idea (or at least what I think your idea is) is, among other things, polarity. In order for your spinning object to be kept away from any metal, it would have to be perfectly suspended in a magnetic filled with equivalent pull on every single side (which is a rather hefty problem in and off itself) but then when you start attempting to spin it, the polarities will have locked it into place so it actually can't spin anyway, and if you tried to force it, it would become unlocked and fall out of place.

And, you underestimate the effects of friction. That shit is rather impressive.

 

[Serioli]

I think you have already answered your own question. You would have to keep the magnet moving which would take energy and because of energy losses (friction/heat) it would take more energy to keep the magnet ahead than you would get from the object being pulled by magnetism. Same thing if you use electromagnets, more energy required than is produced so a total/net loss.

 

[Timotheus]

Whenever a magnet moves something, this object loses its energy stored in the distance to the magnet. You have to pull the magnet and the thing apart which means you have to put in the same amount of energy.

 

[Randomspike]

As Lenz's law states "An induced current is always in such a direction as to oppose the motion or change causing it", meaning that magnets obey Newton's third law of motion.

 

[cp2u]

there was a perpetual motion machine made by using magnets to move a metal ball along a round track, but after testing, it was decided to be incredible energy efficient (3 days in a vault and the ball had only slowed by a tiny amount) but not a perpetual motion machine.
http://www.youtube.com/watch?v=us7YB7eiOeQ

 

[DiMono]

Perpetual motion is possible in the form of objects in orbit due to gravitational pull in a frictionless environment (i.e. planets orbiting the sun), or objects spinning in a frictionless environment (i.e. planets rotating in space). The problem is that as soon as you lose any energy, to anything, you are doomed to failure.

 

[Irony's Acolyte]

I only have a 12th grade level of physics education so keep that in mind. I was thinking about how energy cannot be created, and how magnets seem to break this rule.

If a bigger magnet pulls a metal object, it has done work on the object. But did the big magnet "lose" some of its magnetic power? No, right? So doesn't that mean magnets can do work forever (or until they wear out, if they do)?

Anyone who's a physics nut care to explain why we haven't gotten something like this invented yet? Using magnets to spin something would create friction in some way or another, but if the only loss of energy is through friction would it mean tis pretty damn efficient? And for all intents and and purposes is a very good machine for making energy?

I guess the problem is keeping the metal object from reaching the magnet, since then the "energy" will stop?

http://knowyourmeme.com/memes/troll-sciencetroll-physics

I think that about sums it up. IT'S TOO DAMN SIMPLE. And awesome.

OT: friction can be a *****.

Yeah that's what I was thinking when I read this.

Its seems like a good idea at first, but I really doubt that the people who think up how to get energy haven't already tried to work that out and found out it just wasn't do-able.

In other meme-related news: Magnets, how do they fucking work?

 

[Subzerowings]

Magnets, how do they work?
I was under the impression that with any transfer of energy between two objects, a small part would always be converted to heat, which we can't capture and use a energy yet (I think).
Thus, since there is a loss of energy, perpetual mobiles are still impossible.

 

[Timotheus]

Perpetual motion is possible in the form of objects in orbit due to gravitational pull in a frictionless environment (i.e. planets orbiting the sun),

Not even there: There's something called tide friction which made the moon already loose its own rotation.

 

[Unesh52]

I only have a 12th grade level of physics education so keep that in mind. I was thinking about how energy cannot be created, and how magnets seem to break this rule.

If a bigger magnet pulls a metal object, it has done work on the object. But did the big magnet "lose" some of its magnetic power? No, right? So doesn't that mean magnets can do work forever (or until they wear out, if they do)?

Anyone who's a physics nut care to explain why we haven't gotten something like this invented yet? Using magnets to spin something would create friction in some way or another, but if the only loss of energy is through friction would it mean tis pretty damn efficient? And for all intents and and purposes is a very good machine for making energy?

I guess the problem is keeping the metal object from reaching the magnet, since then the "energy" will stop?

http://knowyourmeme.com/memes/troll-sciencetroll-physics

I think that about sums it up. IT'S TOO DAMN SIMPLE. And awesome.

OT: friction can be a *****.

Lol. This troll science stuff is pretty funny.

but...

Why doesn't this work?

 

[Lilani]

From my experience, magnets do at first appear to break this rule, but due to friction can't maintain it forever. The friction between an object and the air around it may not have much of an effect at first, but over the course of an hour or so you can see it take its toll on one of those magnet-based "perpetual motion" things corporate executive-types have on their desk.

So unless you put those magnets into space, or any other environment virtually free of friction, you're out of luck.

 

[zfactor]

Perpetual motion is possible in the form of objects in orbit due to gravitational pull in a frictionless environment (i.e. planets orbiting the sun), or objects spinning in a frictionless environment (i.e. planets rotating in space). The problem is that as soon as you lose any energy, to anything, you are doomed to failure.

Well, it is close to perpetual motion (there if friction in space, it is not a perfect vacuum, there is a bunch of hydrogen out there). But perpetual motion is useless because if you can't use it to do something, which removes energy from the motion machine, which it does not replace, which slows it over time. And planets undergo other forces (besides gravity) which slow them down.

I only have a 12th grade level of physics education so keep that in mind. I was thinking about how energy cannot be created, and how magnets seem to break this rule.

If a bigger magnet pulls a metal object, it has done work on the object. But did the big magnet "lose" some of its magnetic power? No, right? So doesn't that mean magnets can do work forever (or until they wear out, if they do)?

Anyone who's a physics nut care to explain why we haven't gotten something like this invented yet? Using magnets to spin something would create friction in some way or another, but if the only loss of energy is through friction would it mean tis pretty damn efficient? And for all intents and and purposes is a very good machine for making energy?

I guess the problem is keeping the metal object from reaching the magnet, since then the "energy" will stop?

Lenghty relpy incoming:

Your looking at it wrong!

If you pull a magnet which then pulls another object, you have done work on the magnet, which in turn does work on the metal object. You supplied energy to the system, it did not come from the "magnetic power."

And magnets can be used to reduce friction (they use it on trains to get them to go really fast). Magnets can be used to eliminate surfaces in contact, resulting in only air resistance, greatly reduceing the net force from friction.

You can use magnets to spin something (thats what motors do), but only one magnet is stationary (usually two or four on the outside) and the inner part has many electromagnets that are turned on when they get near the stationary magnets to pull the central rotating part in a circle. But in that case, the electrical energy that is lost is changed into motion energy using magnets. (It is easier to describe this with a picture, but I can't find one...)

End lenghty relpy.

It's the laws of thermodynamics. Energy cannot be created or destroyed (ok fine, you can use e=mc^2 to create energy from mass, but it came from the mass!), it has to come from somehwere. In most cases, it is transformed from one form to another. In your case of the magnet pushing something, you supplied the energy, not the magnet. In the motor, electrical energy uses magnets to be trasformed into motion energy.

So no, using magents as an infinite source of energy won't work.

 

[zfactor]

Lol. This troll science stuff is pretty funny.

but...

Why doesn't this work?

Will it gladden you to know that it does?

Of course, you would suffocate eventually because there would be a limited supply of air.

And another problem is the force required to hold up a massive amount of water is MASSIVE.

So that is theoretically possible, if you made a big enough suction on the opposide side (and had it going straight down would help...) and had a small enough tube (that's why it works with a straw, the water sticks to the sides and there is a small amount of suction needed).

But you would fall straight though the water and die. Sorry!

 

[Distorted Stu]

Obligatory statement coming in 3...2...1..

Magnets... how do they work?

 

[zfactor]

Obligatory statement coming in 3...2...1..

Magnets... how do they work?

WELLLL

Some atoms's individial parts (electrons, protons, etc) are positioned just right so they do not have a net magnetic flux of 0 (the electron charges do not cancel out, resulting in a magnetic field that repels like charges and pulls unlike charges). If enough of the atoms are lined up in a given material, the net flux is enough for humans to notice it, and -BAM- magnet.

If you want to get into why particles have positive of negative charges, then you have to get into quantum mechanics and what not because that involves quarks and fermions and stuff I don't know about...

Long story short: Magnets work, don't ask questions, just accept it!

 

[Unesh52]

Will it gladden you to know that it does?

Yes.

But you would fall straight though the water and die. Sorry!

Really? You wouldn't float like in a normal pool? I mean, I can see how you could swim out of the bottom, but still. Speaking of, might it be possible to stick your head out of the bottom for air?