F//s---> Choose 1 Force // distance
                        2              displacement

book have 1 example: work done against friction when it's case is roller-coaster use distance
but no example of work done of curve line movement so it is Choose 1 or 2 ar!

it should be one``` cuz the work done by friction means that the roller-coaster is in contact with the track the whole time.. so w.e distance the roller-coaster travel on the track times the frictional force is the work done by friction