Question

Two point charges q₁ = 25nC and q₂ = -75nC are separated by a distance of 3.0 cm. Find the magnitude and direction of (a) the electric force that q₁ exerts on q₂ and (b) the electric force that q₂ exerts on q₁.

Answer 1

$$F=k\frac{q_1q_2}{r^2}$$ $$F=9*10^9*\frac{25*10^{-9}*75*10^{-9}}{(0.03)^2}=0.019\:\rm N$$

(a) toward q1

(b) toward q2