b) the electric force the q, exerts on q,. Illustration : + 91 - a z 4 cm cm 10? 2 7 70 ? 1 Solution : Free -body diagram : Since the two charges have opposite signs, the force is attractive. Charge q, will tend to pull q, towards its location and, simultaneously, charge q, will tend to pull q, towards its location a) 290 = 4 1 2 = (9 .0 *10 ? -? 2/? 2, (+ 25 ? 10"(," ? .3) ( -75 ,z ?10 -?)| = 0.019 ? , westward 00