Re: [Phys-l] starting a swing

[Stefan Jeglinski <jeglin@4pi.com>]

> 	Interesting topic.  Clearly, if the swing and rider were a closed
> system, the swinging would never get starte.  So what is there about the
> system that keeps it from being closed?

Based on the "need" for tension (beyond that due to the mass of the 
rider) in the rope to start the process, I would think it is a 
connection thru the rope, to the anchor (swivel point), which is then 
ultimately connected to the earth (via tree limb or swing set poles). 
The only true closed system in this regard is the 
swing-rider-rope-earth system.


Stefan Jeglinski