Question

1. the olympic record for the marathon is 2 hr, 9 min, 21 s. if the average speed of a runner achieving this record is 5.436 m/s, what is the marathon distance?

Explanation:

Step1: Convert time to seconds

First, convert 2 hr, 9 min, 21 s to seconds.
2 hours = 2×3600 s = 7200 s.
9 minutes = 9×60 s = 540 s.
Total time $t=7200 + 540+21=7761$ s.

Step2: Use the speed - distance formula

The formula for speed is $v = \frac{d}{t}$, where $v$ is speed, $d$ is distance and $t$ is time.
We know $v = 5.436$ m/s and $t = 7761$ s.
Rearranging for $d$, we get $d=v\times t$.
$d = 5.436\times7761$
$d=42195.796\approx42195$ m.

Answer:

42195 m