An object travels North at #8 m/s# for #3 s# and then travels South at #6 m/s# for # 7 s#. What are the object's average speed and velocity?

Question

An object travels North at #8  m/s# for #3 s# and then travels South at #6  m/s# for #  7   s#.  What are the object's average speed and velocity?

Nathan Ashcroft · Accepted Answer

average speed: 6.6 m/s
average velocity: 1.8 m/s South

Object travels North at #8m/s# for #3s# #rarr# object travels #8m/sxx3s=24 m " North"# then it travels South at #6 m/s# for #7 s# #rarr# object travels #6m/sxx7 s=42 m " South"# Total distance traveled: #24 m +42 m =66 m# Total displacement from point of origin: #color(white)("XXX")24 m N +42 m S=-24m S +42 m S=18 m S# Total time involved in travel: #3 s+7s=10s# #"Average speed" = ("total distance")/("total time") =(66 m)/(10 s)=6.6m/s# #"Average velocity"=("total displacement")/("total time")=(18 m S)/(10 s) =1.8 m/s S#

Isabella Alvarez · Answer

undefined Average Speed: $ \frac{{\text{{Total Distance}}}}{{\text{{Total Time}}}} = \frac{{8 \, \text{{m/s}} \times 3 \, \text{{s}} + 6 \, \text{{m/s}} \times 7 \, \text{{s}}}}{{3 \, \text{{s}} + 7 \, \text{{s}}}} = 5.2 \, \text{{m/s}} $

Average Velocity: $ \frac{{\text{{Displacement}}}}{{\text{{Total Time}}}} = \frac{{0 - 24}}{{10}} = -2.4 \, \text{{m/s}} $ (Southward)