# The Naked Scientists Forum

### Author Topic: What is the force exerted by a magnet?  (Read 9919 times)

#### Joe L. Ogan

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##### What is the force exerted by a magnet?
« on: 17/01/2010 21:29:51 »
What is the force exerted by a magnet?  Sometimes it attracts.  Sometimes it repulses.
It works on some things and it does not work on other things.  It appears to have some connection to electricity but it must be somewhat indirect.  Just what is it?  How did it get there?  Why does it work as it does?  Thanks for comments.  Joe L. Ogan

#### Pmb

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• Physicist
##### What is the force exerted by a magnet?
« Reply #1 on: 20/01/2010 04:53:46 »
What is the force exerted by a magnet?  Sometimes it attracts.  Sometimes it repulses.
It works on some things and it does not work on other things.  It appears to have some connection to electricity but it must be somewhat indirect.  Just what is it?  How did it get there?  Why does it work as it does?  Thanks for comments.  Joe L. Ogan
If the force is acting on a charged particle in accordance with the magnetic portion of Lorentz's force law then its the magnetic force. How else to you expect it to be described? Nobody knows what the mechanism is behind it. At least not within classical EM theory. Perhaps in field theory.

The magnetic force neither attracts nor repells. It always acts perpendicular to the velocity of a charged particle. If you're thinking of a bar magnetic attracting or repelling another bar magnet then that's more complicated. In those cases the force is actually an electric force. I.e. think of a solenoid with current running through it. It acts like a bar magnet. The magnetic field from another solenoid exerts a force on the charges which are moving through the wire. The charges which feel this force exert a counter force on the wire and that is the force which moves the magnet. Very complicated and confusing. If you'd like you can read about this in the American Journal of Physics. If you want the journal references let me know and I'll look them up.

#### yor_on

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##### What is the force exerted by a magnet?
« Reply #2 on: 19/02/2010 21:46:47 »
"If you're thinking of a bar magnetic attracting or repelling another bar magnet then that's more complicated. In those cases the force is actually an electric force."

PmB are you then adding the force of moving them together too as giving this new electricity? Or is the thought that there is a 'potential' electric force always existing, and when released in the interaction, as they 'touch' each others field, then is seen as an 'electric force'?

And do you mean that there then will be a 'current' running? But not when separated, or?
« Last Edit: 19/02/2010 21:48:35 by yor_on »

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##### What is the force exerted by a magnet?
« Reply #2 on: 19/02/2010 21:46:47 »