Displacement
Elementary
Think of a moving object, like a ball rolling across a floor. The displacement of the object is how far, and in which direction, it ended up from where it started.
High school
Consider an object that moved from a starting point $P$ to an ending point $Q$. The displacement of the object is its change in position, as a vector from $P$ to $Q$.
Examples
Examples
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Walking $3$ m east and then $3$ m west
Elementary
The displacement of the walk is $0$, because the walk ends where it started.
Properties
- The length of the displacement is the straight-line distance between the start and the end, which is at most the distance traveled along the path.
Distinctions involving this term
- Types of difference: Many quantities compare two things by “how far apart” they are. A difference is the result of subtraction and can be negative. No distance is negative. An error compares an approximation with the truth, a change compares the end with the start, and a set difference removes elements.