One video from me and one from the author should help you understand centripetal force. There is also a quiz to the right with one particular question that you'll have to reason out. Finally, take a look at this SCREENCAST for more information. Good luck!
Source: Hewitt, P. G. (2015). Conceptual Physics (12th ed.). Boston, MA: Pearson.
Source: HEWITT, P. G. (2015). CONCEPTUAL PHYSICS (12TH ED.). BOSTON, MA: PEARSON.