QUESTION: several permanent magnets often keep out both forever tend to that have higher push not hard while making a forever magnetically levitated program In which really does the ability to perform the job 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 Biracial dating apps right there is a lingering 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 seem to do really works» questions boil down to similar explanationsan electric field you forgot to think about.
QUESTION: how does the newest electronic force alter for the magnetized force giving specific velocity for the observer i.age. just how try these dos pushes physique oriented?
‘s the newton’s 3rd law of motion are violated right here
ANSWER:Indeed, electronic and you will magnetized fields aren’t something different, he could be symptoms of a single field, the fresh electromagnetic profession. Once you change in one frame away from regard to different swinging physical stature, you change the mix of new electronic and magnetic components of people sphere. Such, a point charges at rest possess a pure electronic field; but if you see it out-of a relocation physique regarding reference, it has got both an electric and you will magnetic career. It’s far too in it to demonstrate the facts right here. Why that people still discuss digital and magnetic fields from inside the elementary physics courses is that, typically, it got very long to see their associations. New electromagnetic occupation isn’t a good vector profession, it’s a tensor field, an area which includes more step three section.
The fresh new electrostatic pushes are reddish and they are equivalent and you will reverse
QUESTION: an electron moving perpendicular to help you a magnetic profession knowledge lorentz push , right here there is step however, where’s the latest «equal and you may reverse» reaction force .
ANSWER: The field is being created by a recent somewhere and «impulse push» is on that cord. However, you to push isn’t necessarily equal and you may contrary on force on electron. Newton’s third rules, as the coached in basic physics, is not actually definitely correct and you can magnetized pushes, because they are velocity established, are the best example to show so it. The new figure suggests one or two self-confident charge swinging with velocities revealed by the black colored vectors. The latest magnetic force sensed by the particle swinging horizontally is actually zero given that profession around (due to the most other fees) is actually no. Industry considering the charges moving horizonatlly issues right up away of your screen, and so the magnetized force (blue) on the other side costs is to the best. The web based push for each particle is actually found from inside the environmentally friendly and he is neither equal nor opposite. Newtonian mechanics takes on new forms from inside the electromagnetism and you may everything nevertheless all depends along with her, you need certainly to through the time and you will energy densities out of this new sphere. This will be ways not in the scope associated with webpages to address.