Woops, it's the 2010 exam -- my bad. 1. The problem statement, all variables and given/known data They have diagrams that I'm not sure how to display; so find them at the following link: https://aapt.org/physicsteam/2010/upload/2010_Fma.pdf These are #'s 19 and 20 and they refer to the PE graph in 18. 2. Relevant equations Not sure, perhaps: E_mec = K + U 3. The attempt at a solution I'm not at all sure how to use the PE graph and a position vs time graph to find total energy or describe the motion. Also, I'm not sure how a potential energy vs position could give rise to position vs time. If anyone could direct me to the concept or link that I'm missing -- that'd be great.