An object travels North at $15$ $m$ $s^(-1)$ for $2 s$ and then travels South at $2$ $m$ $s^(-1)$ for $7 s$ . What are the object's average speed and velocity?

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Answer 1 · 2017-07-22T06:40:48

The average speed is $=4.89ms^-1$
The average velocity is $=1.78ms^-1$

The total distance travelled is $d=15*2+2*7=44m$

The total time is $t=2+7=9s$

The average speed is

$barv=d/t=44/9=4.89ms^-1$

The displacement is

$Deltax=15*2-2*7=16m$

The average velocity is

$=(Deltax)/t=16/9=1.78ms^-1$

An object travels North at 1515 mm s^(-1)s^(-1) for 2 s2 s and then travels South at 22 mm s^(-1)s^(-1) for 7 s7 s. What are the object's average speed and velocity?