In rockets, the force is the action produced by gas expelled from the engines. According to the law, the greater the gas that is expelled and the faster it accelerates out of the engine, the greater the force or thrust. More details on this law can be found in Rocket Principles . The Newton Car is a kind of a slingshot. A wooden block with three screws driven into it forms the slingshot frame.
Rubber bands stretch from two of the screws and hold to the third by a string loop.
A mass sits between the rubber bands. When the string is cut, the rubber bands throw the block to produce an action force. This experiment directs students to launch the car while varying the number of rubber bands and the quantity of mass thrown off. They will measure how far the car travels in the opposite direction and plot the data on a graph. Repeated runs of the experiment should show that the distance the car travels depends on the number of rubber bands used and the quantity of the mass being expelled.