An object travels North at 6 m/s for 2 s and then travels South at 2 m/s for 8 s. What are the object's average speed and velocity?

Aug 8, 2017

Answer:

The average speed is $= 2.8 m {s}^{-} 1$
The average velocity is $= 0.4 m {s}^{-} 1$

Explanation:

The total distance travelled is $d = \left(6 \cdot 2\right) + \left(2 \cdot 8\right) = 12 + 16 = 28 m$

The total time is $t = 2 + 8 = 10 s$

The average speed is

$\overline{v} = \frac{d}{t} = \frac{28}{10} = 2.8 m {s}^{-} 1$

The displacement is

$\Delta x = \left(6 \cdot 2\right) - \left(2 \cdot 8\right) = 12 - 16 = - 4 m$

The average velocity is

$= \frac{\Delta x}{t} = \frac{4}{10} = 0.4 m {s}^{-} 1$