Average velocity = (displacement) / (total time)
Displacement = distance and direction between
the starting point and the end point
The car travels 90 meters north, then 40 meters south.
So it ends up 50 meters north of where it began.
Displacement = 50 meters north
Total time = (15 + 5) = 20 seconds
Average velocity = (50 meters north) / (20 seconds)
= 2.5 m/s north
