# Homework Help: Is it possible to pump a swing 360 degrees?

1. Dec 14, 2011

### rlaworms

Is it possible to "pump" a swing 360 degrees?

1. The problem statement, all variables and given/known data
Is it possible to "pump" a swing so that it turns in a complete circle? Assume if you wish that the seat of the swing is connected to its support by rigid rod rather than a rope or chain.

2. Relevant equations
Angular momentum
Li=Lf
3. The attempt at a solution
We know that we can decrease or increase the rotational inertia by standing or crouching on the swing, respectively. However, we are not completely sure if those inertias alone will make it possible to swing in a complete circle.

2. Dec 14, 2011

### PeterO

Re: Is it possible to "pump" a swing 360 degrees?

I have seen performers at a "humans only" circus [like cirque du soleil] do it!

Edit: They were using a reasonably "short" swing, much shorter than you see in a children's park, and did it in the standing position, so will have been working with a reasonably small moment of interia? and yes, rods not chains.

3. Dec 15, 2011

### rlaworms

Re: Is it possible to "pump" a swing 360 degrees?

Oh, thanks. I kind of understand the question now.

So, it is possible to swing 360 degrees...