1. The problem statement, all variables and given/known data A system loses 400 J of potential energy. In the process it does 400 J of work on the environment and the thermal energy increases by 100 J. Show this process on an energy bar chart. 2. Relevant equations Ui + Ki + Wext = Uf + Kf + change in thermal energy 3. The attempt at a solution I drew a bar with value +400 J for Ui, +100 J for Ki, and -400 J for Wext. Then I drew a bar of +100 J for change in thermal energy. The part I'm not sure about is the +100 J for Ki since the problem doesn't say anything about losing kinetic energy. But that was only way I could think to make the equation balance. Any thoughts would be greatly appreciated.