Figure P31.20 shows a top view of a bar that can slide without friction. The resistor is 6.00 Ω and a 2.50-T magnetic field is directed perpendicularly downward, into the paper. Let ℓ = 1.20 m.
(a) Calculate the applied force required to move the bar to the right at a constant speed of 2.00 m/s.
(b) At what rate is energy delivered to the resistor?