Answer to Question #317987 in Physics for paul

Question

The force in the middle of two identical charges separated by 1.77 cm is equal to 70N. What is the magnitude of the two forces? 

Answer 1

The Coulomb's law says

$$F=k\frac{|q_1||q_2|}{r^2}$$

The magnitude of charges

$$q=\sqrt{\frac{Fr^2}{k}}=\sqrt{\frac{70*0.0177}{9*10^9}}=1.17*10^{-5}\:\rm C$$