# Center of magnetic potential vs center of mass

1. Aug 27, 2013

### nearc

first i might be using magnetic potential incorrectly so please be nice when correcting me.

i'm attempting to model the behavior of a magnetic compass when it is placed next to a ferrous piece of metal. basically the compass will point to the metal rather than north. my first simplification was to consider the metal and the magnet points and to make the math easier i am allowing the metal and the magnet to occupy the same position.

my question: to make a physical representation of the metal and magnet occupying the same position can i make the metal a 'C' shape and the magnet a point in the middle of the C? in other words could i find the center of the magnetic potential of the metal shaped C and treat that as the point location of the magnet?

followup question: can i compute the center of magnetic potential in a similar fashion to finding the center of mass?

thanks

2. Aug 28, 2013

### tiny-tim

hi nearc!

what is centre of magnetic potential ?

3. Sep 2, 2013

### nearc

like i said i might be using the wrong term, let me elaborate: if we had a ring like an 'o' the center of mass would be in the center and if we removed part of the ring and had a 'c' shape the center of mass would be shifted slight to the left but still somewhere in empty space. would could then treat the center of masses of these two objects as points and use them to compute various things such as the gravitational attraction between the two objects, F=Gm1m2/d, where d is the distance between the to center of masses.

what i want to know is can i use the same approach if i had a 'C' shaped piece of ferrous metal and a bar magnet shaped like '-' ? this allow me to place the bar magnet inside the 'C' so that the distance between the center of the magnetic attraction would zero?