$\cdot$ Two high-current transmission lines carry currents of 25 $\mathrm{A}$ and 75 $\mathrm{A}$ in the same direction and are suspended parallel to each other 35 $\mathrm{cm}$ apart. If the vertical posts supporting these wires divide the lines into straight 15 $\mathrm{m}$ segments, what magnetic force does each segment exert on the other? Is this force attractive or repulsive?