Question

A runner moving through a 1600 m course takes 5 minutes and 25 seconds to go 1230 m. What must his average velocity be for the remainder of the course if his average velocity for the whole race was 3.81 m/s

Answer 1

3.89 m/s

Step-by-step explanation:

If we want an average velocity for the whole race of 3.81 m/s in a 1600 m course, the course it must be completed in:

`(1600 \ m)/(3.81 \ (m)/(s) ) = 420 \ s`.

So, the runner already run for 5 minutes and 25 seconds, this is

`5 \ min *60 \ (s)/(min) + 25 \ s = 325 \ s`.

For finishing the course, the runner has

`420 \ s - 325 \ s = 95 \ s`.

Now, the distance that the runner has to cover in this time its:

`1600 \ m - 1230 \ m = 370 \ m`

Finally, the runner average velocity for the remainder will be:

`V= (distance \ left)/(time \ left) = (370 \ m)/(95 \ s) = 3.89 \ (m)/(s)`