A long, thin rod parallel to the y$-$axis is located at x $=-1\mathrm{.}0$ cm and carries a

uniform linear charge density of $+1\mathrm{.}0$ nC$/$m$.$ A second long, thin rod parallel to the z$-$

axis is located at x $=+1\mathrm{.}0$ cm and carries a uniform linear charge density of $-1\mathrm{.}0$ nC$/$m$.$

What is the net electric field due to these rods at the origin?

$4.[5$ points$]$ A $-3\mathrm{.}0-$C point charge and a $-9\mathrm{.}0-$C point charge are initially extremely far

apart. How much work does it take to bring the $-3\mathrm{.}0-$C charge to x $=3\mathrm{.}0$mm$,$ y$=8\mathrm{.}0$mm

and the $-9\mathrm{.}0-$C to x $=-3\mathrm{.}0$mm$,$ y $=0\mathrm{.}0$mm $?$