Re: Does a Magnet's force weaken witht the distance cube?


Randy Poe wrote:
Sue... wrote:
Compare it to the hyperphysics
page. Note that the author is describing an *approximation*
presumably to develop some magnetic approximations
in a later chapter.

The hyperphysics page does exactly the same
approximation, but with potential instead of field.
On the hyperphysics page you will see that a
potential of +kq/r is added to a potential of -kq/r
(note that both vary as 1/r, not 1/r^2), almost
cancelling, leaving a residual term which varies
as 1/r^2.

There isn't much use for a static electric dipole but if
you encounter one it plays by the same rules.

Yes, the rules


Consider an ensemble of one proton and two electrons.
A distant charge will see it as a single electron and the
force will diminish by 1/r^2.

All non-symmetric arrangements have fields/potentials/
forces which can be expressed as a sum of moments.
What you are noting here is that when there is a
net charge, the monopole term dominates. The
other terms are not zero however, and so the field
will not fall off exactly as 1/r^2 since this arrangement
is not spherically symmetric.

Yes... showing or imagining electric field loops out
into free space that are not rigorously attributed to other
charges in the universe is really the essence of a
theory that the space has some vague existance
commonly known as a space-time continuum or
an ether. You are showing pictures of the loops
and measuring their existance with imaginary
"test charges" which don't themselves, alter any
loops. If GP-B should detect some dragible continuum
then I would have to give your POV a bit more consideration.
Until that that happens, I have to stand on my notions
that viewers in moving cars don't alter the time it
takes a raindrop to reach the ground and Jupiter
can't put on two different shows for two different
twins just because one is moving. You and I
have to agree to disagee so long as a world
view can't be eliminated on the basis of the
mathematical absurditiy or paradox.


However, you avoided discussing a dipole, which is
a pair, not a triplet of charges, +q and -q. What does
THAT look like at a distance? An electron? A
proton?

I repeat, this is freshman stuff you're arguing with,
stuff that any decent high-school physics student
knows a lot better than you. You're making yourself
look like an idiot.

Freshmen are taught that their cable televlsion
will go bonkers and Jupiter will put on private
shows for a traveling twin if the ship is fast enough.
Even earning a Ph.D. doesn't seem to help most of
them find the absurdity in such a notion.

What freshmen are taught is hardly the basis for
a scientific argument.

Sue...

"The best argument against democracy is a five-minute
conversation with the average voter."
--Winston Churchill


- Randy

.

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