Answer to Question #307721 in Electricity and Magnetism for luca

Question

 solve for the Force of 2 charges, q1 = -63 nC and q2 = +42 nC with a distance of 5.5 cm. (Note: ϵ0 has a value of 8.85 x 10⁻¹² C²/ N m²) (C²/ N m²)

Answer 1

The Coulomb's law says

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

$$F=9*10^9*\frac{63*10^{-9}*42*10^{-9}}{(0.055)^2}=7.87*10^{-3}\:\rm N$$