Here's why:
* Speed tells you how fast something is moving. For example, 50 miles per hour.
* Direction tells you which way something is moving. For example, north, east, or 15 degrees south of west.
Velocity combines these two pieces of information. It tells you both how fast something is moving and in what direction.
Example:
* Speed: A car is moving at 60 miles per hour.
* Direction: The car is moving east.
* Velocity: The car has a velocity of 60 miles per hour east.
Key takeaway: Velocity is a more complete description of motion than speed alone.
