1. The problem statement, all variables and given/known data 13 equal charges q are placed at the corners of a polygon and as on a clockface, what is the net force on a test charge at the center Q? I assume the charge at the center is positive and the charge on the polygon so they repel 2. Relevant equations (1/4piEo)(qQ/r^2) 3. The attempt at a solution it seems there is a net force in one direction where there is a lack of symmetry in the Fx, Fy. for the situation of q=3 I calculated that there is a net charge upwared of (1/4piEo)(qQ/r^2)(1-2sin(pi/6))=0 with the equilateral triangle pointing upward, sin 30 degrees=1/2 but as n sides of the polygon approaches infinity even in an odd polygon this would resemble a smooth circle and the charges would cancel out with Fnet=0? take out one charge in the 13 sided polygon and the charge motion and electrical force is in the direction of the missing charge?