Well, lets say we have a bike and we wanted to see the maximum speed that the bike would reach down a hill. Lets say that the combined weight of the rider and the bike is 210 lbs. The diameter of the wheels is about 20 inches and the hill is 45 degrees steep. The hill is smooth and has just enough surface tension to hold the bike up. The hill extends infinitively or however long it needs to be for the bike to reach maximum speed at these conditions. I was wondering if this Maximum Speed could be determined mathematically. I have yet to take a physics course, so i really know nothing of mechanics or the such, and i was wondering if someone could show me how we would calculate such a problem.