2 No a- O - 4 3 a - Figure 29-57 Problems 29, 37, and 40.0-40 In Fig. 2957, four long straight wires are perpendicular to the page, and their cross sections form a square of edge length a = 8.50 cm. Each wire carries 15.0 A, and all the currents are out of the page. In unit- vector notation, what is the net magnetic force per meter of wire length on wire 1