I am very new to physics and am taking a my first University Physics class. This is not a call for a problem to be solved, but a clarification on terminology. In solving problems for uniform circular motion, some problems call for the acceleration of the object (a=v^2/r) and others the centripital or instantanious acceleration (a=4pi^2r/T^2). Can you please attempt to explain, in layman's terms, the difference between the two references to acceleration? Thanks for your assistance.