No, an object moving at a constant speed cannot have a changing velocity. Velocity is a vector quantity that includes both speed and direction. If an object's velocity is changing, it means either the speed or direction or both are changing.
If an object is moving at a constant speed, it means the magnitude of its velocity remains the same. However, if the object changes its direction while maintaining the same speed, its velocity is changing. Similarly, if the object maintains a constant direction but changes its speed, its velocity is also changing.
In summary, for an object to have a changing velocity, either the speed, direction, or both must be changing. If an object moves at a constant speed, its velocity will only change if the direction of motion changes.