Hi we're doing a project in class where we make roller coasters and we test them out by sending a marble down them. As a bonus question my teacher asked why there would be an error in the calculations we do (finding speed at different locations of the roller coaster) if we're using a marble... Well I guess it has to do with the fact that the marble is round, and it is not sliding down the roller coaster it is rolling? Would it change the conversation of energy formula? or Ek formula? In our class so far we havnt studied anything rolling... can someone help me out?