The principle of this toy is to show the effects of centrifugal force and the concept of the rip cord combined with the fly wheel propulsion system. The toy works by pulling the rip cord through the car, this will spin the weighted wheels and the centrifugal force will make the car drive. The car will be mostly made of plastic with a strip of metal in the wheel to add weight and therefore create more centrifugal force. There are no small parts so the toy is fairly safe .