Question

Two charges are separated by a distance of 0.03 meters. Identify the magnitude of the net

force exerted by each charge on one another.

q1 = +25 × 10^−9C and q2 = −75 × 10^−9C

Answer 1

The Coulomb's law says

$$F=k\frac{|q_1||q_2|}{r^2}$$ $$F=9\times 10^9\times\frac{25\times 10^{-9}\times 75\times 10^{-9} }{0.03^2}=0.019\:\rm N$$