1. The problem statement, all variables and given/known data (Sorry for my bad English) A slippery (frictionless), light horizontal bar rotates about a vertical axis with a constant angular velocity ω. A cylinder with mass m, is initially attatched to a thread with length a and to a spring, which from the beginning has its "natural" length. Suddenly the thread breaks. Now the maximum distance between the cylinder and the axis is b. Determine the spring constant k for the spring. I have uploaded a picture of the problem. Thanks! 2. Relevant equations 3. The attempt at a solution I know that I should use integration but I don't know how or where to start.