A 2D (two-dimensional) barcode is a graphical image that stores information both horizontally -- as one-dimensional <term>bar code</term>s do -- and vertically. As a result of that construction, 2D...
Centripetal force is the inward-seeking pull of an object. Centrifugal force is the opposite; it appears to pull objects away from the center or axis of rotation.
Centripetal force counteracts centrifugal force, which is not a real force but is the tendency for objects on a circular path to leave the path in a straight line. Finally, tangential velocity is the constant velocity of the object that is perpendicular to the line running from the object to the center of the path.