there are 2 dipoles. One with electrical moment 10pC*m and other 16pC*m. The distance between 2 dipoles is 20 mm. Dipole moments are located on the same line and are pointed in the same direction. The question is what is the force between 2 dipoles. What i have achieved so far: i think a way is to use Coulomb`s law. We look one dipole and add the forces that exist in the one-pole system. the interaction between two dipoles as simply the sum of four pairwise terms which are dependent on the distances between the four charges of the dipoles (pos1-pos2, neg1-neg2, pos1-neg2 and neg1-pos2). i know that p=q*l l is distance between +q and -q in one pole. in that summing equation i dont know l1, l2, q1, q2. There is also force of field E. When i have one dipole and whatever distance r from its center then E=k*p/r^3. But how to use this knowledeg remains yet a mystery for me. Can someone help me?