what are examples or centripetal acceleration?

Centripetal acceleration is necessary, and is present, whenever any object moves in a closed path, or along any part of a circular path.  Some examples I can think of are:-- a planet or a comet in orbit around the sun-- a moon in orbit around a planet-- the little ball making circles around the spinning roulette wheel-- a stone tied to the end of a string, when you spin it around your head-- the end of the spinning string on a weed-whacker -- the tip of the blade of a fan or a windmill-- any little bit of rubber on a car tire or bicycle tire, when they're moving-- a strawberry seed spinning around the inside of the blender jar when you're making a smoothie  -- a car driving around a curve in the road -- you on almost any amusement park ride;  whenever you're not moving in a straight line, you're experiencing centripetal acceleration.

centripedal acceleration :⇒ the moon in orbit around a planet (or the sun).⇒ The Earth (or an other planet) in orbit around the sun.