Magnetism and electrical charges?

Question

Suppose you have a permanent magnet that is attached to a mass sitting on a surface. The attraction is strong enough that you can pull the mass via a string attached to the magnet. This is not an "idealized system" - i.e. there is energy lost through friction and air resistance. Yet, you can pull this mass as long and as far as you want without any change in the properties of the magnet. There is energy output from the magnet, since it is supplying the force to pull the mass. But where does it come from? Does this somehow violate the Law of Conservation of Energy?

How is it that two charged particles supply the energy to repel or attract one another without changing their characteristics?

Yes, I know it's the magnetic/electrical fields. And that's generated by the charge. But HOW?

You are pulling the magnet - the magnet is pulling the mass.

mass --(mag force) -- magnet --(tension)-- person

Answer 1

Cool question.

I'll start with the first question, the magnet, string and mass.

Your mistake is in thinking that the magnet is suppling the force to pull the mass. It is not. You are, by pulling the magnet via the string. Any losses to friction will be made up by you, the force pulling the magnet.

Id est, the magnet is not suppling any real engergy to the system. It is creating an internal force which is attracting the mass. As to how this is happening, there are several different answers and they all come from quantum physics. Search google if you want to long run down of the different theories. The most basic of which says that the magnet is actually exchaning what are called "force" particles with the mass to create the force of attraction, similar to the way proton and neurtons exchange force particles to exert the weak and strong force on each other in an atom.

So no, this does not violate the law of conservation of mass/energy. You are providing energy by pulling the magnet.

Second question, how do charge particles repel or attract one another?

Also, several theories on this one, once again all quantum in nature. What you're really asking is, "What is an electric or magnetic field?" The simple answer is a property of the universe. The long answer involves once again, an exchange of tiny force particles that you can only see in a particle accelerator. I.E. the charged particles actually exchange smaller particles that carry the engery of the force that we see as electromagatism.

If you want to read a really good easy to understand book on this, pick of The Tao of Physics.

Answer 2

A magnet is a storehouse of the energy. The fact governing the magnetic energy is the Molecular Theory Of Magnetism, according to which the molecules in a magnet are in a form, such that the positive end of one molecule touches negative end of another, and so on. So, on the poles of the magnet, there is huge magnetic force. The magnetic force depends on the type of magnet. According to the magnetic influence the magnets are of given types: Temporary magnets, Permanent magnets and Electromagnets.

IN the given question, the use of permanent magnet in the experiment has been indicated. Hence, we are clear that it has huge amount of magnetic energy than any other type of magnet. Hence, we are clear that the energy by which the magnet attracts the mass comes from within itself. We cannot interpret that given phenomenon violates the Law of Conservation of Energy, because in this phenomenon the magnet is attracting the mass, but there is nothing such that the energy is being created or destroyed. We are not creating or destroying the magnetic energy of the magnet, but instead we are viewing the magnetic effect on the mass. We are just the audience, and we are not violating the magnetic property of the magnet.

When two charged particles come close to each other, they attract or repel each other. similar charges repel, while dissimilar charges attract. Hence, there is only the change in the physical state of the charges (whether they attract or repel), but no chemical change takes place. And there is change in characteristics only if there is chemical change. But in this question, there is no chemical change.
That's all I can say about this question.
Thank you.

Answer 3

Magnetic feilds eminate from the movement of the electrons in anything; it normally cancels itself out in everyday objects because the electrons are going in all sorts of directions. In the magnet, the electron movements are aligned so that many of them are going the same direction and creating the same field, and it all adds up to a measurable force. When you put a little pressure on this feild, it in turn puts pressure on the electrons, and their rotation direction can be a little affected, so the magnet can potentially release some of it's energy, but that's not what we are really talking about here.

The total work of the magnet in your case sums to zero. You are pulling the string, which moves the magnet in one direction. The string delivers the force to the magnet, which similarly delivers the force to the object. Or in other words, you have a real string and a magnetic string. The work done is by you, overcoming the inertia of the entire system and the friction of the object through your two "strings".

No one really understands magnetism that well, like gravity, nuclear forces, biological forces, and conciousness. It is suspected by many that all the forces in the universe are different versions of a single force, which would be something like "intention". However, back to the question, they are not supplying the energy, they are storing the energy temporarily, and when they release it, they do change their characteristics, including their mass (e=mc2).

As mentioned earlier, the magnetic feilds are generated by the movement of the electrons. The bigger fields are made by lots of electrons moving in unison, and the power comes from whatever is making the electrons move, such as the blow of a hammer to a crystal or the stored chemical reactions in a battery. They are merely the delivery system, or the "string".

At least that's my take on it.

Answer 4

Well, since you're supplying the force, you are also doing the work. The magnetic field is actually not doing any work here because the magnet and mass are at rest with respect to each other. So no, there is no energy output from the magnet. No violation of energy occurred because the same energy you're supplying is doing an equal amount of work on the mass.

Your second question is improperly worded because charged particles do not supply energy in creating an attraction or repulsion of another particle. The particles create a field in which other particles react.

Answer 5

There is in fact no energy output from the magnet: there is a force, but there is no change in distance between the magnet and the plate to which it attaches, so no work is done by the magnet. All the work that is done is by you, pulling on the string. Work was negatively done when the magnet was originally placed in proximity to the plate (by reducing the energy of the magnetic field); positive work will have to be done (in an equal amount) to pull them apart again.

In the case of electrostatic charges, they have a potential energy which can be turned into other energy (photons) if there is an attraction between them. Suppose that you have an oxygen nucleus in your microscope, and toss electrons at it. The first eight will stick, and each one that adheres will toss a photon of appropriate energy to reduce the total energy to that required to maintain the orbital. You will then have a neutral oxygen atom; if it finds another one, they will pair up to form a molecule, again tossing a photon in the process.

This is, of course, not a complete answer to your question: you are looking for some underlying mechanics, on the presumption that in fact there are some. But it appears that there really aren't -- all we can do is describe what happens, and not worry too much about why.

Answer 6

The attraction properties of a magnet do not expend energies. It is an inherent property of the material. The magnetic atraction is there regardless of the proximity of any nearby metal.

The permanent magnet is not exactly permanent. The "charge" given to the magnet will gradually weaken, by itself, over time. There would have been a relatively huge expediture of energy in creating the permantent magnet, either electrically or mechanically. It is that energy that eventually winds down.

Answer 7

But HOW?

:-)

Nobody knows how.

We know why it happens and when can measure it with precision, what makes it happen.... ahh that's the question for the 64k... think of it as gravity, we know that it works and we can predict what it will do but what is gravity? nobody knows... not just yet.

[edited to add a comment on P's answer]

"The long answer involves once again, an exchange of tiny force particles that you can only see in a particle accelerator. I.E. the charged particles actually exchange smaller particles that carry the engery of the force that we see as electromagatism."

You are stating this as fact, and it is not so. While it could very well someday be proven correct AS OF TODAY nobody knows this to be the case. Take for instance the explanation Wikipedia gives for magnetism

---------
Physics of magnetism

Magnetic forces are fundamental forces that arise from the movement of electrical charge. Maxwell's equations and the Biot-Savart law describe the origin and behavior of the fields that govern these forces. Thus, magnetism is seen whenever electrically charged particles are in motion. This can arise either from movement of electrons in an electric current, resulting in "electromagnetism", or from the quantum-mechanical spin and orbital motion of electrons, resulting in what are known as "permanent magnets". Electron spin is the dominant effect within atoms. The so-called 'orbital motion' of electrons around the nucleus is a secondary effect that slightly modifies the magnetic field created by spin.

When given a treatment with relativity in mind, depending on the frame of reference, electromagnetic forces acting on an object partition differently into magnetic and electric fields. In fact, for this reason, magnetism can be considered a direct consequence of relativity.
---------

You should notice that they do not attempt to explain HOW it is happening or what it is, only why it is happening.

Answer 8

the person is supplying the energy to pull the string that is attached to the magnet that if attracted to the foreign metal. And the charges are caused by the reaction of electrons and protons reacting with each other.

Answer 9

Good quesiton- so far, the specific energy hasn't been identified per se- that is to say we know protons, electrons, neutrons, and some Japanese imports known as Futons for sleeping on. But nobodys come up with a "mangaton" yet, and gravatrons are only theoritical.

We do know it has something to do with the alignment of the molecules that somehow break down into smaller magnets. When I was in college and they showed this I was like "Gee, its just like breaking down a bolder into small rocks and pebbles but you didn't really answer the quesiton of WHAT IS IT?"

So, they still don't know. Good Luck

Answer 10

Inthe case of the magnet the magnetic is not supplying energy, it is merely transferring energy from the string to the mass.

In the case of the charged particles energy is transferred between them.

In both cases energy is conserved and there isa no need to call the physics police.