1. The problem statement, all variables and given/known data http://img694.imageshack.us/img694/1115/pendulumcutquestion.jpg [Broken] Please ignore the blue pen. 2. Relevant equations Ek=1/2 mv2 Ep=mgh 3. The attempt at a solution Basically I looked at the problem firstly as the pendulum has reached the lowest point, therefore having an Ep of 0 and an Ek . Then I took a final point, where the string is cut. At this point there is Ek and Ep is there not? The height would therefore be from the bottom of the swing, to the place where it's cut, which equals 6.4 - 6.4cos(30) So now I have this Ek= Ek2 + Ep 0.5mv2 = 0.5m(vsin30)2 + mgh Am I on the right track? What do I do after this? I don't know what my next move should be... Should I use the point where the string is cut , and set it equal to the ball at the top of the height's energy?