A 10-cm-long wire is pulled along a U-shaped conducting rail in a perpendicular magnetic field. The total resistance of the wire and rail is \(0.20 \Omega\). Pulling the wire with a force of \(1.0 \mathrm{~N}\) causes \(4.0 \mathrm{~W}\) of power to be dissipated in the circuit.

a. What is the speed of the wire when pulled with a force of \(1.0 \mathrm{~N}\) ?

b. What is the strength of the magnetic field?