An object travels North at #5 m/s# for #6 s# and then travels South at #8 m/s# for #4 s#. What are the object's average speed and velocity?

1 Answer
Jun 30, 2018

Answer:

Refer to the explanation.

Explanation:

The total distance traveled was:

#5 \ "m/s"*6 \ "s"+8 \ "m/s"*4 \ "s"#

#=30 \ "m"+32 \ "m"#

#=62 \ "m"#

So, the average speed is:

#bars=d/t#

#=(62 \ "m")/(10 \ "s")#

#=6.2 \ "m/s"#

I'll take North to be the original direction for velocity. So, the total displacement is:

#5 \ "m/s"*6 \ "s"-8 \ "m/s"*4 \ "s"#

#=30 \ "m"-32 \ "m"#

#=-2 \ "m"#

So, the displacement is #2 \ "m"# south.

The average velocity is therefore:

#barv=(vecd)/t#

#=(-2 \ "m")/(10 \ "s")#

#=-0.2 \ "m/s"#

This means that the average velocity is #0.2 \ "m/s"# south.