When we talk about motion or rest it is with reference to some point known as origin. So now with respect to the change in position we have two quantities which can be used to describe that change in position, they are distance and displacement. So now the question is, what is the difference between the two?
Talking about distance, it is defined as the total path length covered during the motion. It can be represented only by magnitude. On the other hand displacement is the shortest distance between the initial and final position. It requires both magnitude and direction for complete representation. Let’s analyze them graphically:
Now if someone asks what is the distance between A and B is, we can’t give a definite answer because it depends on the path taken. It may or may not be same for all the three paths. But for displacement, we can always give a definite answer as it is a straight line joining the two points. In other words, displacement is nothing but the shortest distance between the two points, which in this case is Path 2. Also, it has a particular direction from A to B as we can see.
So now that we have a basic idea of both we will try to solve an example: Suppose the distance between two cities A and B is ‘d’. A person goes from A to B and returns back. Calculate distance travelled and displacement.
Distance travelled = Total path length covered
= d + d
Talking about displacement, it is measured as the shortest distance between initial and final position. In this case, both are same and hence, displacement is also zero.
So for a motion, can displacement be greater than the distance covered? Think about it, and if not can it be equal?
Stay tuned with Byju’s to learn more about motion in a plane, velocity and much more.