Hi, 1. The problem statement, all variables and given/known data You've hung two very large sheets of plastic facing each other with distance d between them, as shown in Figure P26.50 ( http://i137.photobucket.com/albums/q208/infinitbelt/p26-50-1.gif [Broken]... ). By rubbing them with wool and silk, you've managed to give one sheet a uniform surface charge density n1 = -4(n0) and the other a uniform surface charge density n2 = 5(n0). What is the electric field vector at points 1, 2, and 3? 2. The attempt at a solution I drew the force diagrams for the three points but that is where I think I am making my mistake. For example, for point 1, I have a force going to the left from the positive plate and a force going to the right from the negative plate. The difference I get is 1(n0), but that is wrong. Any ideas? Thanks!