Science Experiment for kids (Part I)

This 'Jet-propelled car' is powered by an inflated baloon. Stream of air is forced out from the nozzle at high speed an this generates the reaction force required for thrushing the car forward. I built the car with my daughter and she liked it very much. This fantastic toy demonstrates how Newton's Third Law of motion can be applied in everyday life and I strongly recommend this to all physics teachers and those who are interested in science.

Questions:
(1) Can you suggest other applications of Newton's Third Law of Motion?
(2) Rocket propelled cars are not popular, can you suggest a reason for this?