What is the difference between speed and velocity?

The key difference between speed and velocity lies in the fact that velocity includes direction, while speed does not.

• Speed is a scalar quantity, meaning it only has magnitude (size). It tells you how fast something is moving. For example, "The car is traveling at 60 mph."

• Velocity is a vector quantity, meaning it has both magnitude and direction. It tells you how fast something is moving and in what direction. For example, "The car is traveling at 60 mph due north."

Here's a table summarizing the differences:

Feature	Speed	Velocity
Type	Scalar	Vector
Magnitude	Yes	Yes
Direction	No	Yes
Units	mph, km/h, m/s, etc.	mph due north, m/s east, etc.
Example	50 km/h	50 km/h north

Consider this: Two cars could both have a speed of 50 mph. However, if one is traveling north and the other south, their velocities are different (-50 mph south and +50 mph north, assuming a coordinate system). Even if they're going at the same speed, their velocities represent opposite motions. Changes in velocity are also important in physics (acceleration).