a distance runner jogs 5 km around a small lake. she travels the first half of the distance at a constant speed of 4 m/s. she travels the second half of the distance at a constant speed of 2 m/s. what was the average speed of a jogger for the entire trip?

Respuesta :

First half distance is covered by speed 4 m/s

so the time taken by the jogger to complete the distance

[tex]t = \frac{2500}{4}[/tex]

[tex]t = 625 s[/tex]

next half distance is covered by speed 2 m/s

so the time taken by it to cover the distance

[tex]t = \frac{2500}{2}[/tex]

[tex]t = 1250 s[/tex]

now the total time of the journey

[tex]T = 1250 + 625 = 1875 s[/tex]

now the average speed is given by

[tex]v = \frac{D}{T}[/tex]

[tex]v = \frac{5000}{1875}[/tex]

[tex] v = 2.67 m/s[/tex]

so its average speed will be 2.67 m/s