Question

An object travels North at `7 m/s` for `9 s` and then travels South at `6 m/s` for `2 s`. What are the object's average speed and velocity?

Answer 1

`"Average Speed"= 75/11 m/s`
`"Average Velocity"=51/11 m/s`

Explanation:

Object Travel North
Time taken = 9 s
speed = 7 m/s
Travel Distance = `speed * time=7*9=63 m`

Object Travel South
Time taken = 2 s
speed = 6 m/s
Travel Distance = `speed * time=6*2=12 m`

`"Average Speed"= "total distance "/ "total time" =(63+12)/(9+2)=75/11 m/s`

Displacement
object travel 63 m towards North and 12 m towards south
`total displacement=63-12=51 m`

`"Average Velocity"="Total displacement"/"total time" =(63-12)/(9+2)=51/11 m/s`