... Newton's Laws . ... If object A exerts a force F on object B, . then object B exerts an equal and opposite force ?F on object A" . ... There exists a whole set of situations where two equal and opposite forces act on the same object, canceling each other so that no acceleration (or even no motion) occurs. ... It is all in Newton's third law: as your legs propel your body towards the dock, they also apply to the boat an equal force in the opposite direction, which pushes it away from the dock. ...