Ayo-yo is swung around the head of a person in a horizontal circle. what provides the
centripetal force on the yo-yo?

There is a net force towards the center of the circle that causes the yo-yo to seek the center.

Circular Motion Qualities:

-Constant speed

-Accelerating

-Velocity is changing constantly.

Centripetal acceleration perpendicular to the motion causes the object to change direction

a_c=v^2/r

Tangential acceleration in the direction of the motion causes and increase or decrease in speed.