Circular motion with constant speed is considered accelerated motion because the direction of the velocity vector is constantly changing, even though the magnitude (speed) remains the same.

Here's why:

* Acceleration is the rate of change of velocity. Velocity is a vector quantity, meaning it has both magnitude (speed) and direction.

* In circular motion, the direction of the velocity vector is constantly changing. Imagine a car going around a circular track at a constant speed. Even though the speed is constant, the car's direction is constantly changing, meaning its velocity is also changing.

* Any change in velocity, whether in magnitude or direction, implies acceleration.

The acceleration in circular motion is called centripetal acceleration. It is always directed towards the center of the circle and is responsible for keeping the object moving in a circular path.

In summary:

While the speed in circular motion might be constant, the changing direction of velocity results in acceleration, specifically centripetal acceleration, which is directed towards the center of the circle.