science
posted by Emily .
A simple model for a person running a 100m race is to assume the sprinter runs with constant acceleration until reaching top speed, and then maintains that speed through the finish line. If a sprinter reaches their top speed of 11.2ms1 in 2.15s, what will be their total time?

the acceleration is
a = 11.2m/s / 2.15s = 5.21m/s^2
during the 2.15s, the distance
s = 1/2 at^2 = 1/2 (5.21)(2.15^2) = 12.04m
so, the runner runs
12.04m in 2.15s
87.96m at 11.2m/s = 7.85s
total time is thus 10.00s