Hi! I've been needing help with a question in my textbook. It seems so stupidly easy, but I can't get it. (Ironically enough, I understood all the others).. here's the question: A bicyclist rides 5.0km due east, while the resistive foce from the air has a magnitude of 3.0N and points due west. The rider then turns around and rides 5.0km due west, back to her starting point. The resistive force from the air on the return trip has a magnitude of 3.0 N and points due east. Find the work done by the resisitve force during the round trip. Here's what I did: W = Fd W = (3.0N)(5.0km) = -15J since its a round trip, I doubled it and get -30J, but the book says that the answer is -30000J Any help would be greatly appreciated!