Originally Posted By: paul
reactionless propulsion is even being experimented with today.

heres a good example , the box can be considered a closed system
there is no external forces that apply agaist the box , but the
box moves.

click here to watch video

did you even watch the video - the tracks the box travels on are clearly attached to the switch.

Having the box on an electrified track is hardly a closed system. Nor, for that matter, is having it on the ground. Ground = friction.