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?
a = v2/(22v - 200)
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?