Answer:
W = 80.91 J
Explanation:
First we identify the variables we use for the calculation.
[tex]W = \frac{Kq_1 q_2}{r}[/tex]
[tex]q_1 = -6 x 10^{-6 }C[/tex]
[tex]q_2 = - 9 x 10^{-6} C[/tex]
[tex]r = 6 mm = 6 x 10^{-3} m[/tex]
[tex]K = \frac{ \pi \epsilon_0}{4} = 8.99 x 109 N.m2/C2.[/tex]
In order to identify the missing variable, we proceed to calculate the work through the given formula. Substituting these values,
[tex]W = \frac{(8.99 x 10^9) * (- 9 x 10^{-6}) * (- 6 x 10^{-6})} {(6 x 10^{-3})}[/tex]
[tex]W = 80.91 J[/tex]