For this question, we use the Coulumb's law to calculate the force on each particles. In this law, force between point charges are said to be proportional to product of each charge and is indirectly proportional to the distance of both charges. We do as follows:
F= kq(1)q(2)/d^2
= (9x10^9).(1.41 x 10^-5 C).(-1.41 x 10^-5 C)/.44^2
= 4.067 N
