SPEED is a scalar quantity whereas VELOCITY is a vector quantity.
SPEED has no direction whereas VELOCITY has direction.
SPEED is the rate of change of motion whereas VELOCITY is the rate of change of displacement.

**Speed vs Velocity:**

**Definition of Speed:**
Speed is a scalar quantity that refers to "how fast an object is moving." It is the rate of change of distance with respect to time. Speed does not have any direction associated with it, only magnitude. The formula to calculate speed is:

Speed = Distance/Time

**Definition of Velocity:**
Velocity is a vector quantity that refers to "the rate at which an object changes its position." It is the rate of change of displacement with respect to time. Velocity has both magnitude and direction. The formula to calculate velocity is:

Velocity = Displacement/Time

**Differences between Speed and Velocity:**

1. **Direction:**
- Speed does not have any direction associated with it. It only tells us how fast an object is moving.
- Velocity has direction associated with it. It tells us both how fast an object is moving and in which direction.

2. **Scalars vs Vectors:**
- Speed is a scalar quantity as it only has magnitude.
- Velocity is a vector quantity as it has both magnitude and direction.

3. **Change in Position:**
- Speed only considers the total distance traveled by an object.
- Velocity takes into account the displacement or change in position of an object.

4. **Positive and Negative Values:**
- Speed is always positive or zero, as it only deals with magnitude.
- Velocity can be positive, negative, or zero, depending on the direction of motion.

5. **Example:**
- For example, if a car travels 100 km in 2 hours, its speed will be 50 km/h (magnitude only).
- If the car travels 100 km to the east in 2 hours, its velocity will be 50 km/h to the east (magnitude and direction).

In summary, speed and velocity are related concepts in motion, but they have distinct differences. Speed is a scalar quantity that measures the rate of change of distance, while velocity is a vector quantity that measures the rate of change of displacement. Velocity includes both magnitude and direction, while speed only considers magnitude.