1. The problem statement, all variables and given/known data The diagram below shows two pith balls, equally charged and each with a mass of 1.5 g. While one ball is suspended by a thread, the other is brought close to it and a state of equi- librium is reached. In that situation, the two balls are separated by 2.6 cm and the thread attached to the suspended ball makes an angle of 20 ̊ with the vertical. Calculate the charge on each of the pith balls. 2. Relevant equations N = (k(C1C2)/r2 where k = 9 * 109 3. The attempt at a solution My problem here is that I'm dealing with unknowns on both sides of the equation. I have to find out N and x. N = (9*10^9(x^2))/1.3^2 I don't know why they give us the information that the angle is 20 degrees. In any case I figured out the dimensions of the triangle which are 7.2, 2.6, 7.65 but I can't figure out how that helps me.