People sometimes think that distance and displacement are just different names for the same quantity. However, distance and displacement are different concepts. If an object changes direction in its journey, the total distance traveled will be greater than the displacement between those two points.
Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion. Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.
Distance traveled is a scalar magnitude that is measured over the trajectory. Displacement is a vector magnitude that depends only on the initial and final position of the body and which is independent of the trajectory. ... The distance traveled by the body will be 2 πr (the circumference length).
