A set of wires arranged on the corners of a square of side length s each carry a different current, as shown in the figure. the wire in the lower left corner carries a constant current I in the k-direction. the wire in the upper left corner carries a current I1 = -Ik, the wire in the upper right corner carries a current I2 = -12Ik, and the lower right wire carries a current I3 = 5I/2 k. Determine the vector expression for the net magnetic force FB per unit length L on the lower left wire using ijk unit vector notation. Express your answer in terms of the permeability u0 of free space, s, I, and numerical constants