4 Sep
2011
4 Sep
'11
6:35 p.m.
John Sweeney wrote:
I think you must be talking about much slower swings than I'm talking
about. Let's say we have two 130 pound people who swing 3.5 times
around in a balance and swing. Physics geekery [1] says it takes
fourty pounds of force to hold the two of them together. I'd much
rather have that split over two people.
Jeff
[1] Let's approximate the dancers as point masses of 130 pounds nine
inches apart. There are 12 counts of swinging after the balance,
so about six seconds. Rotating 3.5 times in six seconds means 35
times in sixty seconds, or 35 rpm. Force here is M*w*w*r, where
M is 130 pounds, w is 35rpm, and r is 4.5 inches. This gives
20lbf for each dancer, or 40lbf total.
If the lady additionally has their left hand on
the back of the
the gent's right shoulder, then the lady is doing more of the
holding together and the gent can do less.
Centrifugal force is not that great - if you are in balance the
pressure is tiny.