Unit Vectors. A Unit Vector is a vector having length and no units U It is used to specify a direction Unit vector u points in the direction of U. G Often denoted with a hat.u=d Useful examples are the cartesian unit vectors[i,,kI point in the direction of the X, y and z axes R=+rj+「k k Physics 121: Lecture 6, Pg 3Physics 121: Lecture 6, Pg 3 Unit Vectors: A Unit Vector is a vector having length 1 and no units. It is used to specify a direction. Unit vector u points in the direction of U. Often denoted with a “hat”: u = û U û x y z i j k Useful examples are the cartesian unit vectors [ i, j, k ] point in the direction of the x, y and z axes. R = rx i + ry j + rzk