On Sat, Nov 14, 2015 at 5:13 PM, David Roberson <[email protected]> wrote:
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. > The analogy is a strained one. It's an example of using energy that exists in the form of angular momentum in order to produce a linear force on a mass to counteract another force that is already present. If one were to attempt to apply the analogy to the case of the permanent magnet, no doubt erroneously, the electrons in the permanent magnet would be the flywheel, and their angular momentum would be used to produce a force to counteract the force of gravity needed to keep a ferromagnetic weight above the ground. There's hand waving everywhere in attempting to apply this analogy. In the case of the permanent magnet, the ferromagnetic weight is constantly being accelerated away from the magnet by the force of gravity. (Assume the magnet is attached to a rigid body.) Eric
