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There are a lot of videos showing the simple homopolar motors in action. Let's look at this one: http://www.youtube.com/watch?v=6jyraFLqfqE It is supposed to be working due to the Lorentz force.

Electrons go through the magnet, deflect under magnetic field due to the Lorentz force and colliding with atoms in the magnet, rotate it.

But what if electrons would travel not through the magnet itself but through the thin wire put between the battery and the magnet, directly connecting + and - of the battery. In this way electrons would still travel in the same direction in same magnetic field, but in the thin wire, not in the magnet. Would then the magnet rotate?

Now the other video: http://www.youtube.com/watch?NR=1&v=zOdboRYf1hM&feature=fvwp Here electrons travel through the wire but still close to the magnet so we still can assume that electrons are deflected due to the Lorentz force even though magnetic field should be weaker on the side of the magnet.

But what would happen if everything would be glued together: battery, magnet, wire. Would then this system rotate? While the electrons would still travel under the magnetic field they should be deflected and rotate the whole system. But it sounds unphysical. Can somebody explain how it works?

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If the whole thing was levitating, I don't see why it couldn't rotate. Its simply a device that transfers electric potential energy (the battery) into kinetic rotational energy. It doesn't rotate for 'free', it needs to battery's energy. This is no different from a bomb being able to explode on its own. Transfer some inner potential energy to whatever, by whatever mechanism. In this case the device is made such to provide the magnetic scaffoldings to make itself spin with Lorentz force –  Mathusalem Jul 14 '13 at 22:09
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If everything is glued together the magnetic fields of moving charge and magnet would still interact. The magnetic fields would attract and condense on one side of the charge and expand on the other side creating the Lorentz force. The condensing and expanding of the magnetic fields creates a warp in space that gravitates both mass and charge together in one direction as in Einstein's gravitation theory but the space warp acts as a moving wave that deflects both the moving charge and the magnetic mass together.

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The conical magnetic field of a moving charge attracts a external uniform magnetic field condensing both fields on one side of charge and expanding both fields on the opposite side creating a warp bubble in the eather causing a force to gravitate the charge direection to one side of its foward movement taking along the external magnetic field mass resulting in Lorentz force action on charge and mass. The presence of a external uniform magnetic field acts only on the magnetic field of the moving charge which moves by electric or kenetic action resulting in current or mechanical force. The movement of a uniform magnetic field has no effect on a stationary charge since no conical magnetic field of the charge is created by movement of charge through the eather. Thus both the uniform magnetic field external to charge can move together with the charge to create a current since the conical magnetic field of charge warps the external magnetic field moving with the charge.

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I'm pretty sure this is gibberish, and I'm pretty sure it doesn't remotely answer the question –  Mathusalem Jul 14 '13 at 22:15
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