Question

An object travels North at `8 m/s` for `8 s` and then travels South at `3 m/s` for `7 s`. What are the object's average speed and velocity?

Answer 1

Average speed = 5.7 m/s

Average velocity = 2.9 m/s

Explanation:

Distance along north`= "8 m"/cancel"s" × 8 cancel"s" = "64 m"`

Distance along south`= "3 m"/cancel"s" × 7 cancel"s" = "21 m"`

Total distance`= "64 m + 21 m" = "85 m"`

Displacement`= "64 m North" - "21 m South" = "43 m North"`

Average speed`= "Total distance"/"Time" = "85 m"/"8 s + 7 s" = "5.7 m/s"`

Average velocity`= "Displacement"/"Time" = "43 m"/"8 s + 7 s" = "2.9 m/s"`