Question

A person walks 150 meters due east and then walks 30 meters due west. The entire trip takes the person 10 minutes. What is the magnitude and direction of the person's total displacement?

Answer 1

`sumvecx=120m` east

Explanation:

Since displacement is a vector, direction is important.

The motion here is 1-dimensional, so we may select a direction as positive, say east.

Displacement is a straight line drawn from the start to the end.

Hence in this case, displacement :

`vecx=150m` east `+ 30m` west

`=150-30` east

`=120m` east.

(Note, since the trip takes place in 10 minutes, we may say that the average speed (rate of change is distance) is `v=x/t=(180m)/(600s)=0.3m//s`, while the average velocity (rate of change in displacement) is `vecv = (dvecx)/(dt)=(120m *east*)/(600s)` `= 0.2m//s` east.)