Repelling Non-Magnetized Metal

[BigCheese]

So I've just been thinking about how one could possible use Magnets/Electromagnets to repel from a metal.

I came up with the following thought:

Metal is attracted to a magnet because the magnet aligns the electrons in the metal to the opposite of the magnet (ie. a N pole put to a metal will charge the side facing the magnet to be S).

If the metal keeps the charge somewhat after removing the magnet, could you not quickly flip the magnet so that the charge in the metal is now the same as the charge of the magnet?

Of course it would quickly realign the metal to attract, but for an instant wouldn't it repel with like charges?

If that's true, couldn't you repel a metal by quickly reversing the polarity of the magnet faster than the magnetic field of the metal can realign? As the charge began to realign, the magnet would stop repelling, but before it could fall, the pole would be flipped.

Is my logic faulty, or would this just be too impractical to time perfectly? Or is there an easier way to repel a metal without having to align the charge beforehand (the final idea would be to create a frictionless buffer around a metal flagpole).

Thanks!

 

[ZapperZ]

So I've just been thinking about how one could possible use Magnets/Electromagnets to repel from a metal.

I came up with the following thought:

Metal is attracted to a magnet because the magnet aligns the electrons in the metal to the opposite of the magnet (ie. a N pole put to a metal will charge the side facing the magnet to be S).

If the metal keeps the charge somewhat after removing the magnet, could you not quickly flip the magnet so that the charge in the metal is now the same as the charge of the magnet?

Of course it would quickly realign the metal to attract, but for an instant wouldn't it repel with like charges?

If that's true, couldn't you repel a metal by quickly reversing the polarity of the magnet faster than the magnetic field of the metal can realign? As the charge began to realign, the magnet would stop repelling, but before it could fall, the pole would be flipped.

Is my logic faulty, or would this just be too impractical to time perfectly? Or is there an easier way to repel a metal without having to align the charge beforehand (the final idea would be to create a frictionless buffer around a metal flagpole).

Thanks!

Your logic is faulty. If this is true, then ALL metal will be attracted to magnets. Would you like to check if this is true?

Zz.

 

[BigCheese]

I'm assuming the metal to be Steel, not a non-magnetic material.

I'm not quite sure which part of my logic is faulty. If the electrons aren't realigned when in a magnetic field, why exactly then is steel attract to a magnet? If they are realigned, why doesn't it provide a small field of itself?

 

[pallidin]

... couldn't you repel a metal by quickly reversing the polarity of the magnet faster than the magnetic field of the metal can realign?...

Hmmm. I find that to be an interesting comment; worthy of a least some consideration.
Perhaps it's not possible at all, I don't know, but I sense a theoretical plausibility given that electron realignment is much slower than magnetic field propagation.
Just not sure about this. Interesting concept, though.

 

[berkeman]

I'm assuming the metal to be Steel, not a non-magnetic material.

I'm not quite sure which part of my logic is faulty. If the electrons aren't realigned when in a magnetic field, why exactly then is steel attract to metal? If they are realigned, why doesn't it provide a small field of itself?

The material doesn't have to be steel, but your mechanism isn't one of the common magnetic levitation mechanisms. You're closest to levitation via Lenz' Law:

http://en.wikipedia.org/wiki/Magnetic_levitation

Induced currents

Main article: electrodynamic suspension

These schemes work due to repulsion due to Lenz's law. When a conductor is presented with a time-varying magnetic field electrical currents in the conductor are set up which create a magnetic field that causes a repulsive effect.