1. The problem statement, all variables and given/known data 2. Relevant equations ∫BdL = μI 3. The attempt at a solution a) the magnetic field is a circle around the wire so the length of the path is the circumference of the circle which is 2πr ∫BdL = BL = μI B(2πr) = μI B = μI/2πr in this problem it is into the page (right hand rule) b) The force on the top part of the rectangle will be down and the bottom part it will be up but they will cancel because the directions are opposite and B will be the same at each point. The net force on the rectangle will be the sum of the force on the left part and the right part. The force on the left part will be to the right (F1) and the force on the right part will be to the left (F2) so F = F1 - F2 F = ILB1- ILB2 the length is the same so F = IL(B1-B2) = IL(μI/2πr1 - μI/2πr2) = I^2Lμ/2π(1/r1 - 1/r2) r1 = .02m r2 = .05 m I = 6 A L = .1 m F = (36)(.1)μ/2π(1/.02 - 1/.05) = (3.6)(30)μ/2π (to the right) c) I think the net torque is 0 but I am not sure. I think it is because they are on the same plane so sinθ = 0 ???