Question

An object travels North at `6 m/s` for `2 s` and then travels South at `6 m/s` for `7 s`. What are the object's average speed and velocity?

Answer 1

Refer to the explanation.

Explanation:

Average speed is defined through the equation:

`bars=d/t`

where:

• `bars` is the average speed

• `d` is the total distance covered

• `t` is the time taken

So, we get:

`bars=(6 \ "m/s"*2 \ "s"+6 \ "m/s"+7 \ "s")/(9 \ "s")`

`=(54 \ "m")/(9 \ "s")`

`=6 \ "m/s"`

Velocity is given by the equation:

`barv=(vecd)/t`

where:

• `barv` is the average velocity

• `vecd` is the distance covered in a specific direction

• `t` is the time taken

Here, I'll let the standard direction to be north. So, the south direction will be represented as negative.

So, we get:

`barv=(6 \ "m/s"*2 \ "m/s"-6 \ "m/s"*7 \ "s")/(9 \ "s")`

`=(-30 \ "m")/(9 \ "s")`

`=-3.bar(3) \ "m/s"`

Therefore, the average velocity is `3.33 \ "m/s"` south.