1. The problem statement, all variables and given/known data Problem 3.7 Suppose that motion studies of a runner show that the maximum speed he can maintain for a period of about 10 s is 12 m/s. If in a 100-m dash this runner accelerates with constant acceleration until he reaches this maximum speed and then maintains this speed for the rest of the race, what acceleration will he require if his total time is 11 s? 2. Relevant equations a = v2/(22v - 200) 3. The attempt at a solution a = 2.25 m/s2 I've read through the solution. What I don't understand stand, however, is why v here would be the 12 m/s value. Sure, that's the velocity given, but how and why should I know to use 12 m/s? Why do I plug that into the relevant equation? I could say, sure, because it's the only velocity value given, but why that particular value?