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?

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Answer 1 · 2017-04-13T16:47:32

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

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

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

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

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

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

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

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

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