QUESTION: a couple of long lasting magnets tend to keep out each other indefinitely usually that have great push not difficult while making a permanently magnetically levitated system In which really does the ability to perform work come from?
ANSWER:One of the truths of electromagnetism is that a magnetic field never does work, you never get work (create energy) directly from a magnetic field. The explanation is always that an induced electric field is what actually does the work. The case of permanent magnets is more complicated than most to try to explain explicitly, so I will give a similar example, taken from the classic text Introduction to Electrodynamics, David Griffiths, Prentice Hall Publishers. In the figure to the right there is a ongoing current in the loop as indicated and there is a magnetic field pointing into the page in the cross-hatched area. The upward force on the loop is just right so that the weight, mg, levitates. Of course, right now, no work is being done since the force is not moving the mass. But, suppose that the field is now increased so the upward force now exceeds mg. Now the mass starts rising. The magnetic force is doing the work, right? Wrong! Before you increased the field the direction of the electrons’ velocity was to the left (don’t forget the electrons go in the direction opposite the current). But, when the loop starts moving up, the electrons now also have a component of their velocity upward and that gives rise to a component of the force on the electrons which is to the right; but this would reduce the current which we have stipulated to be constant. So the battery in the circuit (which is not shown but has to be there if there is a steady current) has to supply more energy than before and that is where the work done on the rising coil comes from the battery. This is really just Faraday’s law, an induced back EMF in the loop arises because of the changing flux. I know this is not the exact question you asked, but, trust me, all “where does the energy come from when magnetic fields appear to would work” questions boil down to similar explanationsan electric field you forgot to think about.
QUESTION: why does the fresh electric force transform for the magnetic push giving particular speed into observer we.e. just how is actually such dos pushes frame centered?
Is the newton’s 3rd law of motion are broken right here
ANSWER:In reality, digital and you will magnetic areas commonly something different, they are symptoms of one occupation, the latest electromagnetic field. Once you change from body type out-of mention of the some other moving physical stature, your change the mixture of the newest electric and you will magnetized elements of those industries. Including, a place charge at peace has actually a natural electric industry; but when you find it regarding a moving figure of source, it’s got one another an electronic and magnetic job. It’s way too inside showing the details right here. Why we nonetheless explore electric and magnetic fields inside elementary physics programmes is that, usually, it took very long to know the connections. The fresh new electromagnetic field isn’t good vector field, it is good tensor community, a field which includes over step three section.
The electrostatic pushes try purple and are also equivalent and contrary
QUESTION: an enthusiastic electron swinging perpendicular to help you a charismatic career experiences lorentz force , here there can be step however, where’s this new “equivalent and you dating for Religious adults may opposite” reaction force .
ANSWER: Industry is created by a recently available somewhere plus the “reaction push” could well be thereon cable. Yet not, one to push isn’t fundamentally equal and reverse towards the force on the electron. Newton’s 3rd rules, because the trained in elementary physics, isn’t positively true and you can magnetic pushes, because they’re velocity built, are the best analogy to demonstrate so it. The latest contour suggests a few positive fees swinging having velocities found from the black colored vectors. The latest magnetic push noticed by particle moving horizontally try zero given that job around (as a result of the other costs) is zero. The field due to the fees moving horizonatlly situations upwards out of display screen, so that the magnetic push (blue) on the other fees would be to best. The online force for each particle is actually revealed into the green and he or she is neither equal nor reverse. Newtonian auto mechanics performs the brand new variations within the electromagnetism and you can that which you nonetheless all hangs with her, you need include the opportunity and you will impetus densities out-of this new areas. This will be way not in the scope on the website to deal with.
