Question

Two long electrical distribution lines run parallel to the ground and are separated horizontally by a distance d= 4.5 m. They each carry a current of i= 550 A, with the easternmost line running due north and the westernmost line running due south. Earth’s magnetic field in this area has a magnitude of B= 40μT, and it points due north and at an angle of θ= 7.5°below the horizontal (i.e., towards the ground). What is the magnitude of the net magnetic force on each meter-long section of the eastern line? Hint: there are two magnetic forces acting on each line.