Here's why:

* Velocity involves both speed and direction. Instantaneous velocity tells us how fast an object is moving *at a specific moment in time* and in what direction it's moving.

* Vectors have magnitude and direction. The magnitude of instantaneous velocity is the object's speed at that instant, and the direction is the direction of its motion.

Example:

Imagine a car traveling at 60 mph east. Its instantaneous velocity at a given moment is 60 mph eastward. This information includes both the speed (60 mph) and the direction (eastward).

Key takeaway: Instantaneous velocity is a vector because it describes both the speed and direction of an object's motion at a specific point in time.