Answer:
[tex]F_{net} = 3.75\times10^{-5} Newton towards negative axis[/tex]
Explanation:
q1 = -11.5nC , x1 = -1.685m
q2 = 40.0nC , x=0.0000m
q3 = 55.0nC , x3 = -1.195m
Force on charge 3 due to charge 1 (attractive)
By applying coulomb law
[tex]F_{13}=K\frac{q_{1}q_{3}}{r^{2} }[/tex]
r = 1.685-1.195
r = 0.49 m
[tex]F_{13}=9\times10^{9}\times \frac{-11.5nC \times -55.0nC}{0.49^{2}m } \times -\iota[/tex]
[tex]F_{13}= 2.37\times10^{-5} (-\iota) N[/tex]
Force on charge 3 due to charge 2 (repulsive)
[tex]F_{23}=K\frac{q_{2}q_{3}}{r^{2} }[/tex]
[tex]F_{23}=9\times10^{9}\times \frac{-40nC \times -55.0nC}{1.195 ^{2}m }[/tex]
[tex]F_{23}=1.38\times 10^{-5}\times -\iota N[/tex]
[tex]F_{net} =F_{13} +F_{23}[/tex]
[tex]F_{net} = 3.75\times10^{-5} Newton towards negative axis[/tex]