QUESTION: a couple permanent magnets commonly repel both forever often with higher force not hard and work out a forever magnetically levitated platform In which does the energy to do work are 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 really works“ questions boil down to similar explanationsan electric field you forgot to think about.
QUESTION: how come this new digital push changes to your magnetized force giving certain speed towards the observer we.age. just how is actually these types of 2 pushes physique situated?
’s the newton’s 3rd laws of movement becoming broken here
ANSWER:In reality, digital and you may magnetized sphere commonly something different, they are manifestations of 1 industry, the new electromagnetic occupation. After you alter in one physical stature off regard to other swinging physical stature, your alter the blend of this new electronic and you will magnetic elements of those people sphere. Instance, a spot costs at peace have an absolute digital job; but if you find it out of a relocation physique away from source, it offers both an electric and you will magnetic profession. It is way too inside it to show the details right here. The reason that individuals nonetheless speak about digital and you will magnetic sphere in basic physics programs would be the fact, usually, it took lengthy to learn their contacts. The brand new electromagnetic career is not good vector career, it’s an excellent tensor field, an industry which includes more than step 3 elements.
The fresh electrostatic forces try red-colored and so are equivalent and you may contrary
QUESTION: a keen electron moving perpendicular to a magnetic career experience lorentz force , right here there was step but where’s the „equivalent and reverse“ reaction push .
ANSWER: The field is being created by a current someplace and „reaction push“ could be on that cord. Yet not, that force is not fundamentally equivalent and you can reverse towards push to the electron. Newton’s 3rd laws, just like the educated in elementary physics, is not really certainly real and you can magnetic pushes, because they are velocity established, are the best analogy to exhibit that it. The newest contour shows two positive charge swinging having velocities found by the black colored vectors. The magnetized force considered of the particle swinging horizontally are no given that profession here (due to the almost every other charge) is no. Industry as a result Asian Sites dating online of the costs swinging horizonatlly things up away of the screen, and so the magnetized force (blue) on the other side costs would be to the proper. The online push for each particle are shown inside the eco-friendly and you can he could be none equivalent nor contrary. Newtonian technicians performs the fresh variations inside electromagnetism and you will what you nonetheless all hangs along with her, nevertheless need to through the times and you can energy densities away from the fresh new sphere. This might be way outside the scope regarding the web site to deal with.