1. The problem statement, all variables and given/known data What is the electric force between a glass ball with 3.5 µC of charge and a rubber ball with -5.0 µC of charge when they are separated by 5 cm? 2. Relevant equations Colombs Law: F(electric)=K((q(1)*q(2))/r^2) K=8.99E9 3. The attempt at a solution This seems like a simple plug in problem but I'm having a little trouble. First i get the elementary charges of both the glass and rubber balls so 1.6E-19*3.5=5.6E-19 for q(1) and 1.6E-19*5=8E-19 for q(2) So i plug in the numbers i know and get: F(electric)=8.99E9(((5.6E-19)*(8E-19))/(.005^2))=-1.611E-22 I plug this into the program my school uses for physics homework and it tells me im wrong. Can you see where im doing something wrong? please any help is appreciated.