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comment by kleinbl00
kleinbl00  ·  4414 days ago  ·  link  ·    ·  parent  ·  post: Dream physics.
Allow me to introduce you to the workhorse of physics and engineering, the free body diagram:

http://en.wikipedia.org/wiki/Free_body_diagram

In order to use one, you must know all the forces on any given body. In this case, the two forces are gravity, pulling you down from your centroid (the place where if I held you up with a finger, you'd balance) and the chain, pulling you up from where the chain is.

In the diagram above, there would be a mass of "you" pointed down. If there were two chains, there would be half a mass of "you" pointed up at each one. This would be equilibrium - there would be a torque of ("1/2 you")x("+distance from your center of mass to the chain") on one side and a torque of ("1/2 you")x("-distance from your center of mass to the chain"). The torques cancel out and you are at rest.

Now nuke a chain. You are no longer at rest, and torque is no longer canceled out. You would experience an impulse around the only fixed point in the diagram - where the chain meets the seat. This torque would be equal to ("you")x(distance from your center of mass to the chain). It would cause you to spin about that point.

(well, and a whole bunch of complex motion associated with the chain where the math gets decidedly more complicated, but we'll ignore that for this example because it's irrelevant)

Note that this is a one-time impulse, because eventually you would return to equilibrium - with your center of mass underneath the chain. Likely you'd be hanging there at about a 45 degree angle.

TL;DR - if you only want one chain get a tire swing.