Place the rear of the Newton car at the initial location marking.
Set up the Newton car again (Put a rubber band through a loop of string, and attach the ends of the rubber band to the two rear screws and the string to the last screw.).
Make sure the track is still arranged properly (all pencils or dowel rods about 5 centimeters apart and parallel).
Place the medicine bottle or small container in the 'v' of the rubber band. See the image at the right.
Place as many pennies as you can fit in the container, and put a lid on the container.
Do NOT break the string yet!
Place the container full of pennies in the 'v' formed by the rubber band.