Question

A jogger runs in a straight line with an average velocity of 4.7 m/s for 3.3 min, and then with an average velocity of 5.8 m/s for 4.4 min. What is her average velocity?

Answer 1

`5.32857142857/sec) = color(red)("average velocity")`

Explanation:

Take `v_1` as 4.7m/s
`t_1` = 3.3m

Use this equation to calculate the distance

`v_1xx t_1 = d/cancel(t)*cancel(t_1)`

`v_1 xx t_1 = d`

Where dis distance
t is time
v is velocity

Plug in the variables
3.3min must be converted to secs

`3.3cancel(min) xx (60sec)/cancel(min) = 198sec`

`(4.7m)/cancel(sec) xx 198cancel(sec) = 930.6m = d_1`

Do the same for `v_2` that is the another velocity

= `(5.8m)/sec xx (4.4min xx (60sec)/(1cancel(min)))`

= `(5.8m)/cancel(sec) xx 264cancel(sec) =1531.2m = d_2`

`(Deltad)/(Deltat) = "average velocity"`

`Deltad = d_1 + d_2 = 930.6m + 1531.2m = 2461.8`

`Deltat = t_1 + t_2 = 198sec + 264sec= 462sec`

`(Deltad)/(Deltat) = (2461.8m)/(462sec) = 5.32857142857/sec`

`5.32857142857/sec) = color(red)("average velocity")`