posted by Shelby .
At the top of a hill, a roller coaster has 67,500 J of kinetic energy and 290,000 J of potential energy. Gradually, the roller coaster comes to a stop due to friction. If the roller coaster has 30,000 J of potential energy when it stops, how much heat energy is generated by friction from the top of the hill until it stops?
used up 67,500 + 290,000 - 30,000 Joules