Quick question, do we always minus friction energy? Like for example, when a roller coaster goes from up top to down below, with some friction, would it be KE = PE - Energy loss by friction? Where KE means kinetic energy, PE means potential energy. What if the roller coaster goes up instead?

Question

anonymous · Answer

frictional energy is always opposing movement, whether you're going up a hill or down

anonymous · Answer

So always minus it, yes? Thanks! :)