Length and displacement are two quantities which may seem to have a similar meaning, yet have distinctly different definitions and symbolism.
Distance is a scalar quantity that refers to "how much ground a subject has covered" during its movement.Displacement is a vector quantity that describes "how much out of place an object is"; it is the object's overall change in position.
To check your understanding of this distinction, look at the movement depicted in the diagram below. The physics teacher strolls 4 meters Eastern, 2 meters Southern, 4 meters Western, and finally 2 meters North.
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| Photo Credit : Physicsclassroom.com |
Although the physics teacher has walked a total distance of doze meters, her shift is 0 yards. During her action, she's "covered doze meters of ground" (distance = doze m). Yet when Jane is finished walking, Jane is not "out of place" - ... there is no shift in her action (displacement = zero m). Displacement, being a vector number, must target route. The 4 yards east cancels the 4 meters western world; and the two meters south cancels out the 2 yards north. Vector volumes such as shift are direction aware. Scalar quantities such as distance are ignorant of route. In deciding the overall distance given by the physics teachers, the many guidelines of motion can be ignored.