1. The problem statement, all variables and given/known data My problem states that a pith ball hangs at 20 degrees from the verticle and weighs 3 grams. It is moved 10cm by a charged rod. They both have the same charge. It asks what is the charge on the ball in C and approximatley how many excess electrons are on the ball. 2. Relevant equations I have the equation kqq/rsquared 3. The attempt at a solution I found all the sides to the triangle and I do not know where to go from there. I do not know the charges so how can I use the equation with q in it?
10 cm in which direction? x? y? other? And where is the rod in relation to the ball? Is the charge distributed over the entire rod, or is it concentrated at a point? Did you draw a free-body diagram and set up the equations from Newton's second law? You should have 2 equations in 2 unknowns (q and the tension T in the cord from which the ball hangs).