Here's why:

* Velocity is a vector quantity, meaning it has both magnitude (speed) and direction.

* Instantaneous velocity refers to the velocity of an object at a specific moment in time.

* The speedometer only shows the magnitude (speed) of the car's velocity at that moment. It doesn't tell you the direction.

Example: If your speedometer reads 60 mph, you know how fast you're going, but you don't know which direction you're traveling (north, south, etc.).