# The Physics of a swing

1. Jul 19, 2006

### appogee

I need help in determining the forces acting on the supports for a swingset. Do the uprights only act in tension and compression or is there also some bending forces as a person swings as high as they can? Are there any formulas that I can use to determine the forces involved during a swinging event?
Any help would be appreciated.

Appogee

2. Jul 19, 2006

### rcgldr

There's some torque on the support bar, since the chains are mounted onto eye bolts that extend from the bottom of the bar, and the chains produce a horizontal component of force on the eyebolts. This torque force would create some bending of the bars.

Also since the upright supports aren't hinge mounted to the support bar, the slight movement of the bar due to the forces from the swing would create some bending force, as the bar would tend to rotate in the direction of horizontal movement due to the way the uprights are connected, unless the uprights could be connected horizontally.

Here's a short video of a guy doing a quadruple back flip off a set of swinging rings, and view from the bar of the same guy doing a double twisting double layout. It might help you visualize the forces.