# Speed and velocity.

Speed *(rate)* is a scalar quantity measuring distance covered in a time period:

`r = d / Δt`

Velocity is a vector quantity measuring change of space in a time period:

`v = Δs / Δt`

That is, velocity has a point A & B, therefore directionality, while speed is measuring the length of the line drawn while being measured. This difference matters when discussing things like team efficiency.