Joined: 16 Mar 2005
Location: 22° 15' N | 114° 10' E
when the field attract and lifted my car keys to it, where does the energy come from?
If you actually want to understand the physics behind such a phenomenon, you need to learn the fundamental stuff.
Ignoring (i) air resistance, (ii) sound produced when the keys hit the magnet, and (iii) possible changes in internal energies due to deformation, the process in question simply involves converting one form of potential energy (due to the magnetic field) to another (due to gravity).
Consider the two types of potential energy (PE) that the keys possess:
Before: high magnetic PE but low gravitational PE
After: low magnetic PE but high gravitational PE
So, the keys lose magnetic PE but gain gravitational PE.
sleepsleep, you somehow think that objects that move must use up energy constantly, but that is not true at all. The only reason something stops on Earth is due to factors such as friction (with the air, the ground, etc).
Theoretically, you could orbit around a planet (move in circular motion) permanently with no use of energy whatsoever except initially when you place it in orbit. That's because space is a vacuum. However space is not a perfect vacuum, so objects in orbit will eventually fall down, unless powered every so often. (most of the time they end up getting replaced so nobody cares if they come crashing down)
Moving, by itself, does not require energy. It's change in movement (well, momentum) that does. Momentum exists because of this very fact: objects in motion continue to remain in that motion unless energy is applied to them (force requires energy).
So the important question for your "perpetual" engine is the following: can you extract energy from it (i.e. make it move something else, like a piston or lever or whatever you want) while having it not stop?
If the answer is no, then your thing isn't perpetual at all, it's a simple object that stays in motion, which is basic 101 physics. Of course assuming you place it in a void container, otherwise it will stop due to air friction, lol.
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