Question

An object travels North at `2 "m/s"` for `8 s` and then travels South at `5 "m/s"` for `6 s`. What are the object's average speed and velocity?

Answer 1

`"Average Speed"=23/7m/s`
`"Average Velocity"=-1m/s` (direction in South)

Explanation:

`"distance"="speed"*"time"`

North Direction
speed`=2m/s` and time`=8s`
distance traveled in North `=2*8=16 m`

South Direction
speed`=5m/s` and time`=6s`
distance traveled in North `=5*6=30 m`

Total Distance Traveled `=16+30=46 m`
Total Displacement `=16-30=-14m`
(16 m in North and 46 m in South) (taking North Side as positive)
Total Time `=8+6=14 s`

`"Average Speed"="Total Distance"/"Time"=46/14=23/7m/s`
`"Average Velocity"="Total Displacement"/"Time"=-14/14=-1m/s`
(direction in South)