I really don't understand how to start and finish this problem. Please answer in detail?

A conducting rod slides down between two frictionless vertical copper tracks at a constant speed of 3.8 m/s perpendicular to a 0.52-T magnetic field. The resistance of the rod and tracks is negligible. The rod maintains electrical contact with the tracks at all times and has a length of 1.5 m. A 0.74-Ω resistor is attached between the tops of the tracks.