7a: in this problem we will examine an "electric dipole". many systems can be viewed as consisting of equal and opposite electric charges separated by some distance (e. g. the salt molecule nacl). thus, it is important to understand their cumulative electrical effect on their surroundings. using a = 0.1 m and d = 1 m, determine the net electric force on q. then repeat this but use d = 2 m. by what factor did the net electric force change? explain this result. note that the distance d extends from q to the point halfway between the other two charges. b: now use a binomial expansion to expand the electric force from each charge in the dipole in terms of a/(2d). show that after "adding" the electric forces due to each charge that the first remaining term depends upon 1/d3. here is the binomial expansion if |x| < 1.