Im reading a page out of Griffiths about 2 guys holding a wire loop on a railroad car and then traveling through a B field on the track. As the guys travel at a speed v through the B field the electrons will start to move in the conductor. If we view it from the point of the the B field that is created by 2 sheet currents, and these metal plates that create the sheet currents are at rest relative to the rail road. So if I am standing next to these plates and I see these 2 guys go by at a speed v through the B field. I would say that the electrons in the wire moved because of the Lorentz force. Now Griffiths says that if we view it from the railroad car that we will say the electrons moved because of an electric field. But if we are on the rail road car we would see the B field coming towards us. And he says that a changing B field induces an E field. So by Faradays law we will get an emf in the loop. But it seems strange to think of it as an induced E field. Because it is not like we are changing the current. It seems better to think of it in terms of length contraction. The density of the electrons will be length contracted differently then the protons so I will see a net E field because now I have free charge. Is this what he means by induced E field?