One general way of locating a particle (or particle like object) is with a position vector F, which is a vector that extends from a reference point (usually the origin of a coordinate system) to the particle. In the unit-vector notation of Section 3.4, r can be written

and rectangular coordinates ( 3 , 2 , 5 m).

As a particle moves, its position vector changes in such a way that the vector always extends to the particle from the reference point (the origin).

where coordinates (x,y, z ) correspond to position vector rt and coordinates (x,y,z) correspond to position vector .We can also rewrite the displacement by substituting.