Recent content by Rolls With Slipping

  1. R

    Electric Fields with Motional EMF

    This seems fine. A real battery for example has an internal resistance meaning the actual voltage across its terminals is less than its ideal voltage. If you think of the vertical segments as "batteries" then the EMF would be the ideal voltage and the resistance of the wire is the internal...
  2. R

    Electric Fields with Motional EMF

    Right, of course! If there is a current and resistance in a wire segment it will necessarily have a voltage care of Ohm's law meaning there will be an electric field in the top and bottom segments. Got it!
  3. R

    Electric Fields with Motional EMF

    This makes much more sense now. I did not realize this was the complete EMF around a loop. I was only thinking about the first term and conservative/non-conservative electric fields. So for the case I'm discussing even though there are induced electric fields from this charge separation, it...
  4. R

    Electric Fields with Motional EMF

    Ok, I think I'm understanding what's going on? The actual distribution of charge in the circuit is rather complicated. Instead of trying to calculate the EMF from this complicated charge distribution, an equivalent electric field is constructed for calculational simplicity. What this equivalent...
  5. R

    Electric Fields with Motional EMF

    Hmm, I'm not quite following this. There is a charge separation in the wire, right? In your post #4, you discuss the different components of the electric field generated by the charge separation which would be a Coulomb electric field. The current in the long wire is constant and so the magnetic...
  6. R

    Electric Fields with Motional EMF

    Yes, that is right. If the wire has a finite thickness then there would be charge separation in the top and bottom wires which would generate a vertical electric field. However, this vertical electric field wouldn't contribute to the overall electric potential difference around the loop since...
  7. R

    Electric Fields with Motional EMF

    Thanks everyone for your responds. Just to be clear, I understand (at least I think so) how to solve for the current. Here is how I would calculate the current using motional EMF and Faraday's Law. There is charge separation in the left and right wire segments due to the Lorenz force. This...
  8. R

    Electric Fields with Motional EMF

    Suppose I have a wire loop that I am moving away from a very long wire which carries a current upward and I want to find the induced current in the loop. The way I know how to approach this is with either Faraday's Law or motional EMF. My question concerns the motional EMF approach. My...
  9. R

    Is Energy Conservation Preserved in a Circuit with Two Inductors?

    The standard assumption is that the current through an inductor must be continuous such that you don't produce an infinite back emf. However in this case, the current through ## L_1## is finite before opening the switch and the current through ## L_2 ## is zero before opening the switch. When...
  10. R

    Work/Energy in a Magnetic Field

    Nice answer! So it really shouldn't be referred to as "magnetic potential energy" then, right? The change in the potential energy should be the work done by the magnetic force, but the magnetic force can do no work. I guess it is just a shorthand way of referring to the potential energy...
  11. R

    Taylor Classical Mechanics example 4.9

    Static friction can do work. An example would be a box on the back of a truck. If the truck is accelerating, but the box does not slide relative to the truck, then the static frictional force on the box is doing positive work.
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