**Speed** is the rate of change of distance with time.

**Speed (v) = Distance(s) / Time(t)**

Speed is a scalar quantity that refers to "how fast an object is moving."

**a scalar quantity has magnitude only.**

**Speed is directly proportional to distance when time is constant: v ∝ s (t constant)**
**Speed is inversely proportional to time when distance is constant: v ∝ 1/t (s constant)**