This led him to discover his third and final law which is Newton's Third Law of Motion. Newton's third law states that every action or force results in an equal but opposite reaction. This means that if one object crashes into another object, the two objects will break away from each other. Sir Isaac Newton's third law is often proven correct because when there is a car accident, it is proven that when cars collide, the cars bounce off each other. This shows that Newton's study was accurate and it will always be used in science no matter how many years might last.