Solve the following problems:
Problem I: A Thomson's gazelle can run at very high speeds, but its acceleration is relatively modest. A reasonable model for the sprint of a gazelle assumes an acceleration of 4.2 m/s2 for 6.5s, after which the gazelle continues at a steady speed.
Problem II: A gazelle would win a longer race. The best time for a 200 m sprint for a human runner is 19.3 s. How much time would the gazelle take for a 200 m race?
Express your knowledge to solve the above problems.