Re: magnetic fields

[brian whatcott <inet@INTELLISYS.NET>]

Antti,
some years ago, I was fascinated to read about the efforts of a person who
was seeking to introduce a new toy.
It featured several ramps, with ferrite magnets disposed on each side,
arranged to draw up a roller, and more difficult, release it at the summit.

He was convinced that he was on the brink of connecting several of these
ramps in a circuit, so that a roller could travel ..er.. indeterminately long.

There was a little difficulty in the final step, of arranging the roller to
finally reach the initial ramp.

He certainly was not misled about sending a roller up a ramp from a
standing start and down the other side. This is perfectly practical.

The concept that eluded him was that uphill and downhill, when the
'magnetic potential' was accounted for, the roller's progress was always
'downhill'.

Does this help?

Brian Whatcott.


At 08:36 9/6/01 +0200, you wrote:
> Dear list members,
>
> I would like to ask some questions on magnetic field.
>
> 1) Why there is no magnetic potential and magnetic potential energy a=
> ssociated
> with magnetic field? Or is there?
>
> 2) It is clear that magnetic field cannot do work on a moving charged=
> particle.
> But in case of a bar magnet magnetic field seems to do work: it can a=
> ttract a
> piece of iron and displace it. What energy transformation is associat=
> ed with
> this? What changes, if any, take place in the bar magnet and its magn=
> etic
> field? To put it shortly: who pays the bill?
>
> These were the questions asked by my International Baccalaureate high=
> school
> students. I could not answer them. Perhaps you can help me.
>
> Regards,
>
> Antti Savinainen
> Physics teacher
> Kuopio Lyseo High School/IB
> Finland
brian whatcott <inet@intellisys.net>  Altus OK
                Eureka!