If the position of a particle is described by a function of time then it will be p(t)=x(t)x^+y(t)y^+z(t)z^.\mathbf{p}(t) = x(t)\hat{\mathbf{x}} + y(t)\hat{\mathbf{y}} + z(t)\hat{\mathbf{z}}. Then how can you represent it ...