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.
The centripetal force is the only real force. The centrifugal force is something that occurs as a result of being inside a rotating (non-inertial) frame. Shifting to an inertial frame demonstrates there is only a centripetal force. G-force is just a term to reference how many multiples of g (9.8m/s^2) are in a force. It is commonly used in discussions of centrifugal force but could be applied to any force. Similarly, any force can be centripetal.