Rovelli relates the `` forced '' motion of Newton to Aristotle 's `` violent '' motion .
Newton 's `` forced '' motion corresponds to Aristotle 's `` violent '' motion with its external agent , but that Aristotle 's assumption that the agent 's effect stops immediately it stops acting ( e.g. , the ball leaves the thrower 's hand ) has awkward consequences : he has to suppose that surrounding fluid helps to push the ball along to make it continue to rise even though the hand is no longer acting on it , resulting in the Medieval theory of impetus.
Aristotle