What will happen  if we usepermanent magnets............?
154800
From what I know about permanent magnets, the heat is the killer when you get near the transistion temperature of the material.  When you do this, the magnetic domains become randomly aligned again and the pole force gets reduced.  If you keep heating it, you can totally demagnatize the material.  In fact, during the manufacturing process, the material is heated very hot under a very strong magnetic field and cooled, allowing the aligned domains to be "frozen" making a high force pole.  \n\nSo in motor design, the aerodynamics of the rotor, the eddy currents generated while running, and the torque loads, will all contribute to heating the magnets.  If you can master the thermal design, you can make very powerful motors.
194000
It's just like "positive and negative" for magnetism, isn't it?  People say them as though they mean something.  All they really mean is that there are two types of magnetic things--like ones repel, opposite ones attract.  We don't know why it's so, but we feel much better when we can attach a word to it.\n\nWe understand many things about gravity (as we do about magnetism), but we can't explain why it exists in the first place.  That question is not even in the scope of physics, really, because it can't possibly be confirmed or denied by any experiment.  But like many things, we want to believe that we understand it.
128833
Three types of magnets:\n\n-Ferromagnets: Magnets which retain a magnetic field after having been magnetised in a magnetic field.\n\n-Paramagnets: Magnets that only exert a magnetic field when they're in another magnetic field.  They support the magnetic field they're in.  Usually their fields are quite weak compared to the external fields.\n\n-Dimagnets: Magnets that exert a magnetic field when they're in another magnetic field but opposing the field.  (Think: *DI*ametrically opposite).  Again, field intensity created by these magnets typically is very small compared to the external field.\n\nAdditionally, many dimagnetic and paramagnetic materials may become ferromagnetic if they are sufficiently cooled.\n\nPermanent magnets are most often ferromagnetic and will retain their magnetism for a long time even in the absense of a magnetic field.  Over time, however, thermal effects will slowly decrease field intensity, but that takes a long time for permanent magnets.
114658
Get a magnet and try it.\n\nRead the last sentence of the link below:
478897
Yes if sufficient force is applied the force of impact will negate the magnetism. This is because the charged particles (electrons, neutrons, protons) will collide and confuse the flow of energy. Unless you have an elctromagnet then the magnetism will survive.\n\nSometimes if you drop a compass you will also make it useless as they are also magnetic
1137048
Well it is certainly not a "perpetual motion" type of device. Magnets gradually lose their magnetism as their "disorder" increases. Their "disorder" increases when they contribute to "order" in ferrous objects in their proximity. Need to increase the "order" in your magnet? Wrap a coil around it and connect it to a DC source. Different materials will "retain" different amounts of residual magnetism ("order") after the power source is switched off. Natural magnets would have been exposed over centuries to small, but significant electrical stresses during their formation. They too would gradually lose it as their "disorder" increases. To answer your question - magnets owe it to electrical energy imprinted in ferrous memory.
997877
that's sweet here i think is a link for a patent. I was thinking on how to make something like that, accelerating itself but i failed :P another of my questions was proven wrong leading me to the conclusion it is impossible for magnets to be used in mine.\n\nhttp://www.inventhelp.com/contactform_patent.asp?id=106&wcw=overture&GCID=S17330x002&KEYWORD=patent+office&MATCHTYPE=search
199857
A large magnet will do the trick.
1030182
they give you magnet powers so go on and git them.
357714
Some types of metal and other magnets.
140684
I guess it can be magnetized. I don't think there would be any problem even if its in the form of a moebus strip, or any form at all. Anyway I am curious for other answers.
170821
it will lose its magnetising powers
1097908
Iron, cobalt and nickel can be magnetic. They can be made to have polarity. Poles that are alike repel and poles which are not alike attract. A magnet will attract all of them if they are not polarized. If they are polarized, a magnet will attract or repel according to the polarity.\n;-D
1092759
I had the same problem when I learned about both of them. \nBut now think of it in a different way. You are assuming that the magnetic FORCE that magnets have on certain metals. But if you think about it carefully they don't create or destroy energy. \nIf you don't beleive me consider a piece of iron with only gravity working on. But its height is 0 so it has no Potential or Kinetic energy. But now let's say you bring in a magnet. Now naturally that will make the iron bar rise and stick to the magnet. Now a natural assumption would be that you just created potential energy because the height of the iron bar just increased. But now you have to consider the fact that magnet is still putting some force on the Iron bar. So no change in potential energy occured. No change in Kinetic energy occured once the bar stuck to it. and the Energy needed to bring the bar up could be accounted by the energy needed to bring iron bar in. This shows that there was no energy created.  \nI think that you are trying to overthink the problem. I think this should help good luck.
1052987
All of the above.\n\nActually even Magnetism is affected by heat.  Heat a magnet and it will lose its magnetism.\n\nChemical composition will also change.
1164491
Very much. Magnet has nothing to do with earth's magnetic north and south. It has it's own north and south and will very much attract like it does on earth. I think you are confused with compass which will not work in space with no north and south.
402683
Electro-magnets use electricity to temporarily align all of the atoms in a ferrous material to a N-S position. When the electricity is turned off, the atoms return to their original misaligned state, losing much of its magnetivity. It never completely loses all of it, as some atoms will remain in the alligned state, creating a "Gauss" feild around it.