[SOLVED] EM-Force between current wires 1. The problem statement, all variables and given/known data Problem 105 in chapter 27 Tipler and Mosca for those playing at home... A long straight wire carries a current of 20 A, as shown in the figure. A rectangular coil with 2 sides parallel to the straight wire has sides 5 cm and 10 cm with the near side at a distance 2 cm from the wire. The coil carries a current of 5 A. (a) Find the force on each segment of the rectangular coil due to the current in the long straight wire. (b) What is the net force on the coil? 2. Relevant equations good question i used B= (mu)*I/(2*pi*r) [sorry, i cant use latex...] and F=BIL 3. The attempt at a solution The answers are F(2)= 100*10^-4N, F(4)= -0.286*10^-4N For the two sides parallel (the 10cm ones), I found B(a)=0.0002T B(b)=0.0000571T The other two wouldnt be effected cos they're perpendicular F=BIL F(a)=4*10^-4N F(b)=1.14*10^-4N ...which are wrong Is it something to do with the area and hence flux and shiznizzle?