Particles of charge +75(Q1), +48 (Q2), and -85(Q3) μC are placed ina line. The center one is .35 m from each of the others. Calculatethe net force on each charge due to the other two.
Okay, so that's my problem, and I've been looking at thesolution on cramster. This is problem 16.12 from Physics: Principles with Applications (6th)By Giancoli. The formula forthe force on +75 by +48 and -85 is: F75=-K(Q1Q2/r122)+K(Q1Q3/r132)
My question is: where did the negative sign in front of thefirst K come from? The same thing occurs in the next twocalculations. Negative signs are popping up everywhere. Why?
