Consider a particle moving in the xy plane. The position of the particle at any time is given by the position vector
, drawn from the origin to the particle. The displacement of the particle as it moves from i to f in the time interval
to
is equal to the vector
, i.e. the change in the position vector of the particle.
The displacement vector for a particle is defined as being the difference between its final position vector
and its initial position vector
, i.e.
. The SI unit for displacement is the metre (m). The direction of
is from i to f. (Obviously, displacement is a vector quantity.)
