# Question #8fa22

##### 1 Answer

#### Answer:

Can I check if the answer for the final part is actually

#### Explanation:

By Newton's 3rd law, the force pushing the athlete forward cannot exceed the friction provided by the track (otherwise they will slip), The friction provided by the track is

Hence the maximum acceleration

For a race of 800m where the maximum speed is 8m/s, we first need to consider the time taken whilst accelerating from the standing start of 0m/s to 8m/s.

Using

we get to

so

and distance covered in this time whilst accelerating:

Hence the time whilst running at constant 8m/s is given by

so (nearly there!) total time is given by: