Re: simple magnets question

[paul o johnson <pojhome@FLASH.NET>]

If I am correctly visualizing your magnetic disk, Bill, I believe it would have
a simple magnetic dipole field around it. Assuming uniform magnetization of the
disk, the field would be the same whether the disk was stationary or spinning
on axis.

In the plane of the disk, the field is axial so any tangential component of a
charged particle's velocity would create a centripetal acceleration causing the
particle to move in a circle concentric with the disk's axis. Any radial
component of velocity would cause a tangential acceleration. This situation
appears to lead to a standard Keplerian elliptical orbit in the disk's plane.

Out of this plane, the field has a radial component so any axial component of
velocity would cause a tangential force, accelerating the particle in its
ecliptic path.

The field would nowhere have a tangential component so there would never be
additional axial or radial components of acceleration owing to such a field.

Poj
Collin County College

William Beaty wrote:

> Suppose we place an electron in the field of a thin disk-shaped permanent
> magnet which has poles on the opposite faces of the disk, and then we briefly
> rotate the disk on axis.  Assume that everything is stationary at the
> beginning, then reach out and give the disk-magnet a
> twist.  What does the electron do?