Against the Wind One windless day you ride your bicycle at 25 km/h for one hour on a flat road. The next day, you ride 5 km/h into a 20-km/h headwind for one hour on a flat road. Assuming that the force of the wind (the primary "friction" in this case) scales with the square of the relative velocity of the bike and wind, the wind's force is the same on both days. Which ride seemed to take more effort on your part? (a) The ride on the windy day was harder. (b) The ride on the windless day was harder. (c) Both rides were about the same. Explain your answer. This not Homework or anything. My class was discussing this Question, and must of use came up with the C), but not a lot of us came with the same Why? I assumed that Force in both cases are Zero, but the work done on day one would be greater, because I am going at a 5x the speed on the first day. I know my answer is wrong. But can anyone explain why the answer is C?