1. The problem statement, all variables and given/known data A 0.35 kg ball on a string is whirled on a vertical circle at a constant speed. When the ball is at the three o'clock position, the tension is 18 N. What is the tension in the string at 12 o'clock and 6 o'clock position? 2. Relevant equations centripetal force= net force=tension 3. The attempt at a solution I can do most of the problems except this one. Would the tension act as the radius? I wouldn't think so since tension is a force. I drew a free body diagram, but I still can't get the correct answer. I only really need to know how to solve for velocity because centripetal acceleration= v^2/r. then, you just multiply that by mass and add it to Fg, right?