Average speed = (distance covered) / (time to cover the distance)
Average speed = (10m + 10m) / (5sec + 5sec)
Average speed = 20m / 10sec
Average speed = 2 m/s
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Average velocity = displacement/time
Displacement = (distance and direction from start-point to end-point) .
The truck started at point-A and ended at point-A .
Displacement = 0 .
Average velocity = ( 0 ) / (10 sec)
Average velocity = 0