I love that someone actually took the time to analyze the gravitational forces at work in the new Angry Birds Space game. I mean, of course they did – this is the Internet after all.
“With the Work-Energy principle, I can take the bird plus the rock (asteroid) as the system. In this case, there is no external forces on the system and thus no external work. The energy of the system will only consist of gravitational potential energy of the bird-rock system and kinetic energy of the bird (assuming no recoil motion from the rock). I can write this as:
I can’t directly measure the potential energy for this system. But I can look at the kinetic energy.”
http://www.wired.com/wiredscience/2012/03/the-gravitational-force-in-angry-birds-space/