1. The problem statement, all variables and given/known data It says: A car moves at a constant speed of 5.0ms-1 along a 6.0km road against frictional force of 150N per meter. How much work has to be done by the car to maintain its constant speed? 2. Relevant equations W = F*d 3. The attempt at a solution So I just did 150N * 6000m = 900000J = 900kJ But what about the 5ms-1? Is that important? I'm guessing it is since it is mentioned, but I don't know how to apply it. And the answer sheet says 9000kJ (and not 900kJ). Please help me? I'm confused, thank you.