An object travels North at #6 m/s# for #3 s# and then travels South at #5 m/s# for # 7 s#. What are the object's average speed and velocity?

1 Answer
May 20, 2017

Answer:

Average speed is #5.3 m/s#.

Average velocity is #1.7 m/s " South"#.

Explanation:

#"Average speed" = "Distance"/"Time"#

The total distance is #6 m/s * 3s + 5m/s * 7s = 18 m + 35 m = 53m#.

The total time is #3s + 7s = 10s#.

Therefore the average speed is #(53m)/(10s) = 5.3 m/s#.

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#"Average velocity" = "Displacement"/"Time"#

The total displacement is :

#18m " North" + 35m " South" = 17m " South"#

The total time is #3s+7s = 10s#.

Therefore the average velocity is #(17m " South")/(10s) = 1.7 m/s " South"#

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Note that the average speed has no direction while the average velocity does (South).