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Re: [Phys-l] starting a swing



Here is a somewhat analogous situation. You are standing on a large sheet of cardboard on a perfectly smooth floor. Take the cardboard as massless.
Can you change your location on the floor?

Regards,
Jack


On Sun, 8 Feb 2009, Stefan Jeglinski wrote:

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

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