Consider the possibility of the new design for an electric train. The engine is driven by the force on a conducting axle due to the vertical component of Earth's magnetic field. To generate the force, current is maintained down one rail, via a conducting wheel, through the axle, through the other conducting wheel, and then back to the source through the other rail.
(a) Determine the amount of current required to give a modest force of magnitude 5 kN? Take the vertical component of Earth's field to be 10 µT and the length of the axle to be 3.0 m.
(b) Determine at what rate would electric energy be lost for each ohm of resistance in the rails?
(c) Is such a train completely or just marginally unrealistic? Describe.