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?
The average speed is 6m/s; the average velocity is 0.75 m/s North.
First, we must determine the displacement of the object during each time interval.
During the first 9s
During the next 7s
For the average speed , we consider only the total distance travelled and the total time taken
For the average velocity , we consider the net displacement and the time taken. The net displacement has been only 12 m North.