Question

When body is performing uniform circular motion what changes?

Answer 1

When body is performing uniform circular motion, its velocity changes.

Answer 2

When body is performing uniform circular motion then the Uniform circular motion would be described as motion of an object which is the best circle that has the constant speed to high extent.

When object moves in a circle, constantly changing on direction then object is moving tangent on circle.

Direction of velocity vector is direction of object's motion.