Hi, I really need help with this question. Here's the question: "The figure shows a U-shaped conducting rail that is oriented vertically in a horizontal magnetic field. The rail has no electric resistance and does not move. A slide wire with mass m and resistance R can slide up and down without friction while maintaining electrical contact with the rail. The slide wire is released from rest." "Determine the value of a terminal velocity if l = 25.0 cm, m = 10.0 g, R = 0.100 ohms, and B = 0.550 T." I know that V_emf = vlB I = V/R = vlB/R If I can find I, then I could determine v. The problem is they don't give V_emf, so I cannot find I. and I have no idea why would they give the mass for, when generally for this type of problem they don't. Any hints would be greatly appreciated.