An object travels North at 7 m/s for 3 s and then travels South at 9 m/s for 2 s. What are the object's average speed and velocity?

1 Answer
Alan P.
May 4, 2016

Average speed =7.8 m/s

Average velocity =0.6 m/s " North"

Explanation:

Total distance traveled:
color(white)("XXX")7 m/sxx3 s + 9 m/sxx2 s = 21 m + 18 m = 39 m
Total time:
color(white)("XXX")3 s + 2 s = 5 s
Average speed:
color(white)("XXX")(39 m)/(5 s) =7.8 m/s

Displacement:
color(white)("XXX")7 m/s xx 3 s " North" +9 m/s xx 2 s " South"
color(white)("XXX")=21 m " North" +18 m " South"
color(white)("XXX")=3 m " North"
Total time:
color(white)("XXX")3 s + 2 s = 5 s
Average velocity:
color(white)("XXX")(3 m " North")/(5 s) = 0.6 m/s " North"

Related questions
See all questions in Displacement and Velocity
Impact of this question
1303 views around the world
You can reuse this answer
Creative Commons License