Centripetal acceleration and centripetal force
Now that we've covered the basics, it's time to move on to some slightly more difficult concepts: centripetal acceleration and centripetal force. Actually they are not really difficult, but they are frequently misunderstood. Hence, we'll try and clear some of the possible confusion as we go along.
As we pointed out in the section on angular velocity, an object moving in a circle (or in a curved path in general) has a linear velocity that is changing with time because its direction is changing all the time. Therefore, from the definition of acceleration as rate of change of velocity, that means it has a non-zero acceleration―we never said that acceleration means just a change ...