Respuesta :

Given:

An athlete who makes [tex]4\dfrac{3}{4}[/tex] laps in 3 mins 45 seconds on a 400m field.

To find:

The speed of the athlete in m/s.

Solution:

We know that,

Distance covered in 1 lap = 400 m

Distance covered in [tex]4\dfrac{3}{4}[/tex] laps = [tex]4\dfrac{3}{4}\times 400[/tex] m

                                               = [tex]\dfrac{19}{4}\times 400[/tex] m

                                               = [tex]1900[/tex] m

We know that,

1 minute = 60 seconds

3 minutes = 180 seconds

3 minutes 45 second = 180 + 45 seconds

                                   = 225 second

The speed of the athlete is:

[tex]Speed=\dfrac{Distance}{Time}[/tex]

[tex]Speed=\dfrac{1900}{225}[/tex]

[tex]Speed\approx 8.44[/tex]

Therefore, the speed of the athlete is about 8.44 m/s.