* Constant speed: This is true for an object moving in a circle at a *constant* angular velocity. Meaning, the object covers the same distance around the circle in the same amount of time. Think of a car going around a roundabout at a steady pace.

* Constant velocity: This is not true for an object moving in a circle. Velocity is a vector quantity, meaning it has both magnitude (speed) and direction. Since the object's direction is constantly changing as it circles, its velocity is also constantly changing, even if its speed is constant.

Think of it this way:

* Speed: How fast something is moving.

* Velocity: How fast something is moving *and* in what direction.

In summary:

An object moving in a circle can have constant speed, but it will *always* have changing velocity because its direction is constantly changing.