Question on Electrodynamics

[darkenlighten]

Okay so I've been wondering if there is a way to calculate the force on a magnetic material (that is magnetized and producing a magnetic field of its own) from an electromagnet that produces its own field.

 

This is not a trick question or anything of the sort and I've been trying to find detail on this, but I have failed to find how one B interacts with the material of another producing its own field. This question comes about to me when thinking of an electric motor and the force produced by an electromagnet on a permanent magnet.

 

Does anyone have any insight?

[swansont]

http://en.wikipedia.org/wiki/Magnetic_moment#Forces_between_two_magnetic_dipoles

http://en.wikipedia.org/wiki/Magnet#Calculating_the_magnetic_force

[darkenlighten]

Sorry for the delayed response. So from looking at these, they seem to be for a more specific case. Do you know of a more general approach, it does say it is more difficult to find for a general case, but it would be worth learning about.

[JD3E8]

perhaps you could measure the force (magnetic field) of your electromagnet using ampere's law:

 

http://en.wikipedia.org/wiki/Ampere%27s_Law#Integral_form

 

then devise a way to measure the force of attraction of your electromagnet when placed near the magnet u want to measure the strength of (maybe hook a vertical scale to one end of your electromagnet, hinged opposite to the end creating the magnetic field.)

 

then find the difference between the force of attraction when the magnets are near each other and the theoretical force created by the electromagnet when it is not interacting.

[darkenlighten]

I'm attempting to find a mathematical approach instead of an experimental. Also the type of interactions I would like to calculate are not going to be direct repulsion. Knowing the magnetic fields are not the problem, that's the easier part, knowing how they would interact is what I'm trying to find.

 

Thanks for the input.