All this talk of pinning is just fine, but all of this is nicely predicted by the basic laws of electrical induction and the zero resistivity offered by a superconductor, you would expect repulsion or attraction to occur.
Now if this were done in a Vacuum then there would be zero air friction naturally, the superconductor would be easier to keep cold and it could just go on and on and on and on and on. On Wed, Oct 19, 2011 at 10:18 AM, Harry Veeder <hveeder...@gmail.com> wrote: > On Tue, Oct 18, 2011 at 1:15 AM, David Roberson <dlrober...@aol.com> > wrote: > > > >>From: Harry Veeder hveeder...@gmail.com > > > >>If the "law of inertia" is universally true, some sort of centripetal > >>force is required to keep the disc revolving in a circle as it moves > >>above the magnets. I can vaguely grasp how the phenomena of locking > >>preserves the tilt of the disc, but how does locking bring about the > >>necessary centripetal force? > > > >>Harry > > It is a beautiful presentation and raises several good questions such as: > > > > It appears to take force to get the disk to move close to the supporting > > magnetic structure. This suggests that energy has to be applied to the > > system as the force occurs over a finite distance. Then if the disk is > > removed, force again must be applied in the opposite direction. More > energy > > is absorbed by the system of magnet and disk. Now, where does the energy > go > > which is supplied? I understand that a superconductor does not allow > > resistive loss from current flow so I suspect magnet must gain energy. > Does > > it actually become warmer as a result of this operation? > > > > Dave > > > Hmmm it obvious now. Clearly a superconductor can be made to exhibit > both attractive and replusive behaviour simultaneously through the > effect of "flux trapping". The attractive behaviour is what keeps the > disc on the tract. However, when I took undergraduate physics 25 only > the meissner effect which results in repulsion was mentioned. > After doing some on line research I found out it was considerably > more difficult to produce flux trapping with the superconductors that > were available in the 80's. I guess the impractical nature of > demonstrating fluxtrapping meant the phenomena need not be mentioned. > > > Harry > > -- If we doubt we can hardly hope to Shine. Be Alive when you are alive! You can't BE later. "Life" is not important, significant, serious or weighty. Life is a dance to be enjoyed. It is You and I that are important, Living life is at stake! There is no someday. There is no right way. There is only now. Virtue or Vice, a moment of pain for a lifetime of pleasure, or a moment of pleasure for a lifetime of pain. Construction or destruction, it is just a matter of order in which you experience pain and joy, spirit and integrity or weakness of flesh. If you aren't making mistakes, you aren't doing enough. How you feel is feedback on what you are currently doing and not informing you of what to do, don't wait to feel like it. Do it and see how you feel.
