An athlete wants to complete the 4000 m run in 12.0 minutes. After exactly 10.0 minutes of running at a constant speed, she still has 800 m to go. If she then accelerates to 4.0 m/s^2, how much longer will it take her to complete the race?

Answer 1

She is traveling at 3200m/12(60)sec

figure out that.

d=vi*t+1/2 (4)t^2
d is 800, vi is above, solve for t.