Answer
$$F_{2}=0 N$$
Work Step by Step
$F_{2}=\frac{k\times q_{2}\times q_{3}}{d^{2}}+\frac{k\times q_{2}\times q_{4}}{(2d)^{2}}-\frac{k\times q_{1}\times q_{2}}{d^{2}}$
$=\frac{k\times e^{2}}{d^{2}}+\frac{k\times4\times e^{2}}{4\times d^{2}}-\frac{k\times2\times e^{2}}{d^{2}}$
$=\frac{2\times k\times e^{2}}{d^{2}}-\frac{2\times k\times e^{2}}{d^{2}}$
$= 0 N$
