Consider the possibility of the latest design for an electric train. The engine is driven by the force on the conducting axle due to vertical component of the Earth's magnetic field. To build up the force, current is maintained down one rail, viaa conducting wheel, via the axle, via the other conducting wheel, and then back to the source via the other rail.
(a) Determine the amount of current required to give a modest force of magnitude 85 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?