An object travels North at $5 m/s$ for $8 s$ and then travels South at $5 m/s$ for $2 s$ . What are the object's average speed and velocity?

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Answer 1 · 2018-04-28T17:33:48

Speed is distance traveled per unit time, whereas velocity is displacement per unit time.

Recall,

$nu = (Deltax)/t" " bars = d/t$

We will assume an x-y coordinate system to be the reference frame, where south is negative and north is positive in direction.

Let's derive the magnitude of the displacement in each direction given your data,

$Deltax_"N" = (5"m")/"s" * 8.0"s" approx 40"m"$
$Deltax_"S" = (5"m")/"s" * 2.0"s" approx 10"m"$

$Sigmad = 50"m"$ , and
$Sigmat = 10"s"$

Hence,

$bars = (50"m")/(10"s") = (5"m")/"s"$ , and

$nu = (40"m" - 10"m")/(10"s") = (3"m")/"s"$

are the average speed and velocities of the moving body.

An object travels North at 5 m/s5 m/s for 8 s8 s and then travels South at 5 m/s5 m/s for 2 s 2 s. What are the object's average speed and velocity?