1. The problem statement, all variables and given/known data Two cork balls hang with a massless insulating thread to the same support point, both balls get charged equally and consequently spread apart to a new equilibrium position. Given variables: weight cork ball: 0.2 g length thread: 20 cm charge ball: 3.0*10-8C T = tension in thread L = radius between the two balls Horizontal force: F = force from electrical charge (horizontal direction) Vertical force: mg Question (the part wich I can't solve) : find the tension in the threads after adding the charge and the angle θ 2. Relevant equations horizontal force: T sin θ = F = kqq/r2  vertical force: T cos θ = mg  r = 2L sin θ  Horizontal force/vertical force = tan θ = F/mg = kq2/r2mg = kq2/(2Lsinθ)2mg  3. The attempt at a solution See the equations above (they were not given and are part of the attempt at a solution). The problem is that I have to find out the value of sin θ, once I've got that I must calculate T which can be easiest found with equation 2: T = mg/(cos θ) How can I calculate sinθ when I don't know the values of F and r? Thanks to anyone who is so kind to help me with this.