Dropping magnet through vertical aluminum tube

[dougettinger]

A well known physics experiment is dropping a magnet through a vertical aluminum tube.
The magnet slows noticably before passing completely through the tube. Electrical current is created in the aluminum tube thereby creating a magnet thereby creating an opposing magnetic flux to slow down the falling magnet.

My question is whether, theoretically, current is also induced in the magnet and/or forces are exerted on the magnet about its axis ?

Another question is whether the Right Hand Motor Rule or the Left Hand Generator Rule can be applied to this experiment ?

Thoughtfully, Doug Ettinger

 

[technician]

The basic rule is Lenz's law.
The falling magnet causes a changing magnetic flux linkage in the Aluminium tube which causes an emf and a resulting induced current.
The induced current opposes the change causing it... the falling magnet... currents circulate around the aluminium tube to effectively try to 'repel' the falling magnet.

 

[dougettinger]

A problem similar to the subject experiment is posed. How is the de-acceleration calculated for a magnetized object of mass, m, and velocity, v, moving through a conductive material (assume an aluminum tube)? No other force fields including gravity are involved.

The magnetized body has a magnetic field intensity of H = B/u where B = magnetic induction and u = permeability of the medium.

Need help, Doug Ettinger