Magnetic Force: Halving the Distance

AI Thread Summary
Halving the distance between two magnetic poles increases the force of attraction or repulsion, but the relationship is complex and depends on the type of magnets involved. For small magnets with poles close together, the force increases roughly as 1/r^3, while for larger magnets with poles farther apart, it follows a 1/r^2 relationship. In certain cases, small non-saturated disk magnets can exhibit a force proportional to 1/r^6. Additionally, permanent magnets can temporarily strengthen in a magnetic field, affecting the overall force experienced. Understanding these dynamics is essential for accurately modeling magnetic interactions.
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Am I correct in assuming that if the distance between two poles of different magnets is halved, then the force of repulsion (or attraction) will increase while the attraction (or repulsion) will decrease? If the distance is halved, isn't the force quadrupled?
Thanks.
 
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Magnetic Field strength decreases far from the source.

If the source magnet has poles "close" to one another
compared to width (ie, small button or disk magnets),
then the field drops off roughly as 1/r^3 (not 1/r^2).

If the poles are very far apart compared to their width,
(5"x1" bar magnets have poles only about 3" apart)
then their field drops off roughly as 1/r^2 .

A little button magnet in a uniform B-field will
experience almost zero (intrinsic) net Force,
but in a spreading field will experience net Force
proportional to the the distance between poles.

Permanent Magnets (the ones filled with metal)
respond in subtle ways to being in a B-field ...
becoming temporarily stronger than usual,
with extra strength proportional to external B.

So, with small non-saturated disk magnets,
you could get F ~ 1/r^6, (7 in special cases)
but with "well-isolated" magnetic poles that
are almost saturated, F could go as 1/r^2 !

Physics is about *modelling* Nature,
whatever the behavior is that we observe.
 
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