The charges in Figure $19-37$ are held rigidly in

their positions. Determine the direction and magnitude

of the net electric field at point $P.$ Assume the charges

and other quantities are known to two significant figures

$($e$.$g$.,2\mathrm{.}0C).($Hint: Use symmetry to simplify the

calculation.$)$ Ans: $(0\mathrm{.}48$ MN$/$C$)$i $(0\mathrm{.}48$ MN$/$C$)$j