The typical example of this is "I push on the wall with a force →F, so the wall pushes on me with a force −→F''. Mathematically, if we have a force →FAB acting from objec...The typical example of this is "I push on the wall with a force →F, so the wall pushes on me with a force −→F''. Mathematically, if we have a force →FAB acting from object A to object B, Newton's third law tells us that we know there must be a force →FBA acting from object B to object A.