The 4 person chair trick involves four individuals transferring their weight to achieve balance while seated. Each participant supports their own weight through their legs and the legs of the person next to them, creating a stable configuration. Key concepts include center of gravity and moments, where the pivot point is at the head, balancing anticlockwise moments from the center of gravity against clockwise moments from the normal force at the feet. This trick is manageable with practice, as demonstrated in classroom settings.
PREREQUISITESThis discussion is beneficial for physics students, educators demonstrating physical principles, and anyone interested in group dynamics and balance exercises.
Consider each person individually as an object resting on two supports. The weight of each person is supported by 1.) their own legs from the knees down, and 2.) the legs, from the knees down, of the person on whose knees their back is resting. The center of gravity of each person is somewhere between their knees and the point where their back touches the next persons knees, though it is much closer to the latter. I just experimented with getting myself into this position with my back resting on the seat of a chair. If you try that you'll see there's much more pressure on your back than on your feet. In the group situation each person's knees are supporting a little bit of their own weight and most of another person's weight. If you could determine the center of gravity of each person in this position you could work out how much of their weight is supported by their own knees and how much by the knees of the next person.rvgene said:hmm, does it have to do with concepts such as centre of gravity and moments?
for example, the pivot is at the head, and there is a anticlockwise moment due to the centre of gravity and a clockwise moment due to the normal force at the feet?