Question

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 11.2ms-1 in 2.15s, what will be their total time?

Answer 1

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

Answer 2

a simple model for a person running the 100m dash is to assume the sprinter runs with the constant acceleration until reaching top speed, then maintains that speed through the finish line. if a sprinter reaches his top speed of 11.2 m/s in 2.14 s, what will be his total time