Figure $29-63$ shows wire 1 in cross section; the wire is long and straight, carries a current of 4.00 $\mathrm{mA}$ out of the page, and is
at distance $d_{1}=2.40 \mathrm{cm}$ from a surface. Wire $2,$ which is parallel
to wire 1 and also long, is at horizontal distance $d_{2}=5.00 \mathrm{cm}$ from wire 1 and carries a current of 6.80 $\mathrm{mA}$ into the page. What
is the $x$ component of the magnetic force per unit length on wire
2 due to wire 1$?$