Answer:
[tex]F=1.26*10^{-3}N[/tex]
Explanation:
Assuming the pith balls as point charges, we can calculate the repulsive force between them, using Coulomb's law:
[tex]F=\frac{kq_1q_2}{d^2}[/tex]
We observe that the magnitude of the electric force is directly proportional to the product of the magnitude of both signed charges([tex]q_1,q_2[/tex]) and inversely proportional to the square of the distance(d) that separates them.
Replacing the given values, where k is the Coulomb constant:
[tex]F=\frac{8.99*10^{9}\frac{N\cdot m^2}{C^2}(-30*10^{-9}C)(-30*10^{-9}C)}{(8*10^{-2}m)^2}\\F=1.26*10^{-3}N[/tex]
