10-cm-long wire is pulled along a U-shaped conducting rail in a perpendicularmagnetic field. The total resistance of the wire and rail is 0.20 Ω. Pulling the wire with aforce of 1.0 N causes 4.0 W of power to be dissipated in the circuit.

What is the speed of the wire when pulled with a force of 1.0 N?
What is the strength of the magnetic field?