91影视

The charges are aligned as given in the figure:

According to superposition principle:

$\begin{array}{r}{\mathbf{F}}_{\mathbf{x}}\mathbf{=}{\mathbf{F}}_{\mathbf{21}}\mathbf{鈭�}{\mathbf{F}}_{\mathbf{31}}\mathbf{cos}\mathbf{鈦�}\mathbf{胃}\\ {\mathbf{F}}_{\mathbf{y}}\mathbf{=}\mathbf{鈭�}{\mathbf{F}}_{\mathbf{13}}\mathbf{sin}\mathbf{鈦�}\mathbf{胃}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\end{array}$

x direction of force is given by

$\begin{array}{r}{F}_x=\frac{k{q}_1{q}_2}{r_1^2}+\frac{k{q}_1{q}_3}{r_2^2}脳\frac{x}{r_2}\\ =\frac{9脳{10}^9脳5脳{10}^{鈭�9}脳2脳{10}^{鈭�9}}{(0.04{)}^2}鈭�\frac{9脳{10}^9脳5脳{10}^{鈭�9}脳6脳{10}^{鈭�9}脳0.04}{{\left[(0.04{)}^2+(0.03{)}^2\right]}^{3/2}}\\ =鈭�3脳{10}^{鈭�5}\mathrm{N}\end{array}$

y direction of force component is given by:

$\begin{array}{r}{F}_y=\frac{k{q}_1{q}_3}{r_2^2}脳\frac{y}{r_2}\\ =\frac{9脳{10}^9脳5脳{10}^{鈭�9}脳6脳{10}^{鈭�9}脳0.03}{{\left[(0.04{)}^2+(0.03{)}^2\right]}^{3/2}}\\ =鈭�6.5脳{10}^{鈭�5}\mathrm{N}\end{array}$

Therefore, the x and y components of the total force exerted on q₃are $-3脳{10}^{-5}N$and $鈭�6.5脳{10}^{鈭�5}\mathrm{N}$respectively.

Magnitude of f is given by

$\begin{array}{r}F=\sqrt{F_x^2+F_y^2}\\ =\sqrt{{\left(3脳{10}^{鈭�5}\right)}^2+{\left(6.5脳{10}^{鈭�5}\right)}^2}\\ =7.15脳{10}^{鈭�9}\mathrm{N}\end{array}$

The angle is given by

$伪=\arctan 鈦�\left(\frac{6.5}{3}\right)={65}^{鈭�}$

But is in 4^th quadrant so add 180

$伪=65+180={245}^{鈭�}$

Therefore, the magnitude of this force is $7.15脳{10}^{-9}N$and the direction is $245掳$from +x axis.