1. The problem statement, all variables and given/known data A 0.60 kg sphere rotates around a vertical shaft supported by two strings, as shown. If the tension in the upper string is 18 N, calculate the tension in the lower string. 2. Relevant equations ƩFR = maR FT = m * (v2 / r) I am not sure about this, but I also think that the equation to find the centripetal acceleration may come in handy as well. 3. The attempt at a solution I am not quite sure how to approach this problem. I tried to use the same methods that were used for a similar problem found here: http://www.educator.com/learn/physics/physics-b/jishi/circular-motion-part-1.php?ex=1 (It is extra example #1), but I do not feel confident in this approach. Physics is not my strongest subject, so please forgive my utter cluelessness. My best guess for this problem is to perhaps solve for the acceleration of the top small triangle where String #1 is the hypotenuse, and then use that answer to solve for the tension of the bottom string. Please correct me if I am wrong, and if you have any tools to help with understanding Uniform circular motion (or physics in general), please let me know. Thanks for the help!!