The mass at the end of the string must initially be moving upwards at a rate that matches the speed at which the small wheel is turning if you want to have a system that is continuous without a major acceleration at zero time. When the mass reaches the bottom of the wheel it will reverse the process. After the same amount of time elapses as required to reach the bottom, the mass will be moving downwards at the original speed but in the reverse direction. Also, the wheel will be rotating in the opposite direction.
Overall, this appears to be an example of a torque being applied to a flywheel that causes its angular momentum and angular energy to change with time. I do not see the analogy with the permanent magnet since that case is representative of a force being applied to a system that is not being accelerated in any manner. Perhaps you would find it interesting to consider what should happen when a metal conductor initially placed within a super conducting magnets field region is removed. A current will be induced within the metal as soon as it begins to move out of the field. You will find the metal acting like it is being retarded by a sticky substance as you apply force to move it. The force you apply through the distance moved requires energy to be expended by you. This energy must show up in several ways. The first is in the typical kinetic energy due to the change in velocity of the metal which is no suprise. Some of the energy will cause the metal to heat up due to the current flowing within it due to the changing field. Also, you will have changed the current flowing within the superconducting magnet windings to a minor degree. That current change depends upon the type of metal that you pull out of the field. Your mechanical example appears to be difficult to compare to the magnetic ones, but perhaps I am missing your point. Would it make sense to compare the systems of a magnetic holding up a piece of iron to a rock placed under the mass holding it up against gravity? No energy is transferred to the mass in either case. Dave -----Original Message----- From: Eric Walker <[email protected]> To: vortex-l <[email protected]> Sent: Sat, Nov 14, 2015 12:35 pm Subject: Re: [Vo]:Re: How many atoms to make condensed matter? On Sat, Nov 14, 2015 at 11:07 AM, David Roberson <[email protected]> wrote: The reason that the flywheel is slowing down in rotation is due to frictional loss at the bearing. Also, the stored angular momentum is slowly dissipating. Here I have in mind a transfer of the kinetic energy of the flywheel to the potential energy of the thing that's being held up (a weight, say): We can allow the bearings of the flywheel to be frictionless, and nonetheless the flywheel will slow down as its kinetic energy is transferred into the gravitational potential energy of the weight. This principle does not seem to apply to the domains in the permanent magnet holding up a weight of similar mass. (Just to be clear, I'm not arguing against conservation of energy, only that there's something strange going on.) Eric
