Question

An object travels North at `5 m/s` for `2 s` and then travels South at `1 m/s` for `2 s`. What are the object's average speed and velocity?

Answer 1

Total distance travelled by the object is `5*2 +1*2=12 m`

And,net displacement of the object is `1*2 - 5*2=-8m`

negative sign means direction of displacement is towards North.

Now,average speed =Total distance covered/total time taken=`(12/4)=3 ms^-1`

And,average velocity =Total displacement/Total time taken `=-8/4=-2ms^-1` and its direction is towards North.

Remember average speed is a scalar quantity wheras average velocity is a vector quantity