Unit Vector
A dimensionless vector with a magnitude of exactly one, used exclusively to specify a direction in space.
Governing formula
û = u / |u|
SI unit
Dimensionless
In depth
Unit vectors along Cartesian axes are designated i, j, k. Multiplying a unit vector by a scalar magnitude yields a complete directional vector quantity.
Examples in the real world
Expressing a 50 N force along the y-axis as F = 50j N.