An object travels North at 6 m/s6ms for 6 s6s and then travels South at 3 m/s3ms for 7 s7s. What are the object's average speed and velocity?

1 Answer
May 1, 2018

Avg. Speed = 57/7 ms^-1Avg.Speed=577ms1
Avg. Velocity = 15/13 ms^-1Avg.Velocity=1513ms1 (northwards)

Explanation:

Avg Speed = (Total Dist.) / (Total time)AvgSpeed=TotalDist.Totaltime
= (6xx6 + 3 xx 7)/(6 + 7) = 57/13 m/s=6×6+3×76+7=5713ms
(Distance = Speed x Time)
Total Displacement is 36 - 21. The object went 36 m north and then 21 m south. Thus it is displaced by 15 m from its origin. Avg. Velocity = (Total Displacement)/(Total time)Avg.Velocity=TotalDisplacementTotaltime
= 15/(6+7) = 15/13 m/s=156+7=1513ms

You may wish to specify that the displacement is in the north direction.