An object travels North at $8 \frac{m}{s}$ $8 m/s$ for $9 s$ $9 s$ and then travels South at $6 \frac{m}{s}$ $6 m/s$ for $7 s$ $7 s$ . What are the object's average speed and velocity?

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Answer 1 · 2017-07-02T14:41:11

The average speed is $= 7.125 m s^{- 1}$ $=7.125ms^-1$ and The average velocity is $= 1.875 m s^{- 1}$ $=1.875ms^-1$

The total distance travelled is $d = 8 \cdot 9 + 6 \cdot 7 = 114 m$ $d=8*9+6*7=114m$

The total time is $t = 9 + 7 = 16 s$ $t=9+7=16s$

The average speed is

$¯ v = \frac{d}{t} = \frac{114}{16} = 7.125 m s^{- 1}$ $barv=d/t=114/16=7.125ms^-1$

The displacement is

$Deltax=8*9-6*7=30m$

The average velocity is

$=(Deltax)/t=30/16=1.875ms^-1$

An object travels North at 8 m/s8ms8 m/s for 9 s9s9 s and then travels South at 6 m/s6ms6 m/s for 7 s7s7 s. What are the object's average speed and velocity?