Difference Between Distance and Displacement

Let's try and understand the difference between distance and displacement.

 Distance is a scalar quantity. It is a physical entity which is used to describe the motion of an object in terms of the path traveled by the object. Simply speaking, distance is the total length of the path traveled by an object irrespective of the direction.

In a one-dimensional frame of reference, let's say the origin or reference point is represented by O. At time t, the body is at a point, P which 10 meters away from O. The object started moving and reached to the point P by traveling 50 meters at time t2 and reached to the point R at time t3 by traveling 100 meters and traveled back to Q by traveling 25 meters.  Q is 135 meters away from the point O.

The total distance traveled by the object is following:

10 + 50 + 100 + 25 = 185 meters

 Displacement is a vector quantity. It is defined as the change of position of the object with respect to a reference point.

Taking above example, the displacement of the object is the following:

OQ - OP

=> 135 - 10 = +125 meters in the positive direction.

What if the object moved further back from Q to another point R, 130 meters away. This point is 5 meters away from O.

The displacement of the object can be calculated as the following:

OR - OP

=> 5 - 10 = -5 meters is the negative direction.





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