An object travels North at #6 m/s# for #9 s# and then travels South at #6 m/s# for #7 s#. What are the object's average speed and velocity?

1 Answer
Feb 20, 2017

Answer:

The average speed is 6m/s; the average velocity is 0.75 m/s North.

Explanation:

First, we must determine the displacement of the object during each time interval.

During the first 9s

#d=vxxt = 6m/sxx9s = 54m# North

During the next 7s

#d=vxxt = 6m/sxx7s = 42m# South

For the average speed , we consider only the total distance travelled and the total time taken

#v_"ave" = d-:t = 96 m-:16 s = 6 m/s#

For the average velocity , we consider the net displacement and the time taken. The net displacement has been only 12 m North.

#vecv_"ave"=vecd -:t = 12m N -: 16s = 0.75 m/s # North