Three long wires all lie in an $x y$ plane parallel to the $x$ axis. They are spaced equally, $10 \mathrm{~cm}$ apart. The two outer wires each carry a current of $5.0 \mathrm{~A}$ in the positive $x$ direction. What is the magnitude of the force on a $3.0 \mathrm{~m}$ section of either of the outer wires if the current in the center wire is $3.2 \mathrm{~A}$ (a) in the positive $x$ direction and (b) in the negative $x$ direction?