1. The problem statement, all variables and given/known data This is the simplest example: But I have to generalize with more pulley things on it. How does the pulley affect the kinetic energy of the car on the air track, and the potential energy of the block pulling the car? 2. Relevant equations Nothing quantitative 3. The attempt at a solution When I conducted this experiment, I noticed that the potential energy of the block and the kinetic energy of the car did not match up in the end, so I'm thinking the pulleys had to do something with it (it used two of them). Does some of the energy get transferred to the pulley system?