Question

What force is there between two charges, each with 2.0 x 10^-6 C if they are 0.03 m apart?  

Answer 1

$$F=k\frac{q_1q_2}{r^2}$$

$$F=9*10^9*\frac{2.0*10^{-6}*2.0*10^{-6}}{0.03^2}=40\:\rm N$$