Question

A runner hopes to complete the 10.000 m run in less than 30.0 min. After running at constant speed for exactly 27.0 min, there are still 1200 m to go. The runner must then accelerate at 0.20 m/s2 for how many seconds in order to achieve the desired time?

Answer 1

Answer:

4 sec

Explanation:

Runner's average speed has been 8900m/1620s = 5.49 m/s.

Runner has 1100m left and must complete it in 180 seconds.

Runner's speed must become 5.49 m/s + (.2 m/s^2)(t seconds) = 1100m/180s = 6.111 m/s

Solving for t gives 3.086 seconds, so round it to 3 seconds...but he might want to make it 4 seconds to beat his goal.