I’ve this office toy, it’s a round flat magnet that get stuck to the underside of one of those storage things you can hang on the side of a cubicle. I’ve hung 4 strands of little round ‘buckyball’ neodymium magnets from it, and the bottoms of the strands repel each other. While they’re almost vertical at the top, the strands curve away from each other at the bottom.
So, they’re exerting force on each other, stronger than gravity, constantly. Where does the energy required to produce this force coming from? What’s getting ‘used up’? Will they continue to repel each other forever?
Will they continue to repel each other forever? YES !
Or am I totally thinking about this wrong? YES , because you had this idea of forever…
Work= Force x Distance.
Power = Work / time = force x distance / time = force x speed
Compare to a helicopter. It should be able to hover and not use fuel ? well its force come from moving air, air has a speed. The air is moved by moving props. They have a speed…
My understanding (to be corrected by one more knowledgable than I) is that the energy comes from the atoms themselves which are like tiny magnets but only make a macroscopic magnet under certain conditions (metal, below the curie point, atom arrangement etc.). Not only is magnetism stronger than gravity, it is magnitudes stronger.
We’re living on a big electromagnet. It has magnetic poles. Some materials (iron, for instance) have a natural tendency to maintain this magnetic energy, and thereby become magnets themself.
ETA: Actually the above is a major oversimplification, but 'twill do until a physicist can come along.
A piece of iron lies on the ground. I hold a magnet over it, and the magnet attracts the iron such that it jumps up and sticks to the magnet. Where did the energy to move the iron come from?
Yes, but, again, way oversimplified. You might check out magnet, magnetism and magnetic field on Wikipedia for the physics, if you want the technical nitty-gritty. Magnetism itself is based on motion of subatomic particles, which provides the impetus.
It came from the energy required to create the magnet and move it with respect to every thing else in the universe. Once a magnet is created there is a magnetic field. Every thing in the universe has some potential energy with respect to that magnetic field.
I don’t think that’s true. Gravity is an example of a force in which there’s no “transfer of energy” and nothing gets “used up” in order to exert that force.
why couldn’t the piece of iron stay still and everything else have moved?
batteries meaning a collection of smaller units is true. an electron spinning produce a magnetic field. if you add all these magnetic fields of all its electrons, then the result is no magnetism for most things and some magnetism for very few things that have had certain unique conditions imposed on them at some time.
The energy is the electromagnetic force contained in the protons and electrons of the atoms involved. In each individual electron, the force seems to us to be very, very, very, very tiny. But their are billions and billions of electrons involved which, together, becomes a force that we notice as we see a few ounces of metal jump an inch. Scale it up and a magnet the size of a manhole can lift a car.
It’s the same force holding atoms into molecules which in turn cling to each other through electromagnetism that give solid objects their solidity. It’s why a chair doesn’t collapse when you sit on it.
So, where is the energy in the electron coming from? From the electric charge inherent in the electron. It’s always there. Just like its mass is always there. And just like its gravitational pull is always there.
But just because its charge is always there doesn’t mean you can get a perpetual motion or work machine out of it. An electron with its negative charge will seek to move (and cause work) to its lowest rest state. Once it does that, it’s not giving you any more work even though its negative charge is still ‘on’ and ‘active.’ This is similar to gravity. For example, once you drop a weight and it hits the ground, it’s not giving you any more work until you lift it up and drop it again, even though its gravitational force is still on and active.
So, once the electrons in a magnet use their negative charge to move a piece of iron until they collide, then you’ve just used up all the work they’re going to do for you unless you put more energy back into the system to separate them.
Just like gravity is always ‘on’ holding you to the earth, so is the magnetism of the electrons always ‘on’ holding a piece of iron to a magnet. Neither system can provide a perpetual motion machine/work without some other outside force adding energy (like the sun evaporating water and fighting gravity to rise and then fall as rain creating rivers flowing downhill and stopped by a dam so that the water can turn turbines attached to magnets to create an electric current).
The piece of iron lost energy when it jumped up and stuck to the magnet. Stuck to the magnet, the iron is at a lower potential energy state than it was when sitting on the ground. You might object and say that it must be at a higher energy state since it moved further away from the Earth, but the energy potential gradient created by the magnet is locally much stronger than the gravitational force exerted by the Earth. Note that in order to move the iron away from the magnet, you will have to spend energy, moving the iron to a higher potential energy state where it isn’t stuck to the magnet.
No, the carrier is the photon. The electrical and magnetic properties are combined with the Maxwell equations so it’s mor properly thought as an EM field than just the magnetic field.
