system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What's the physics behind moving the arms in a looping motion when we're out of balance?
gpt
Conservation of angular momentum. If you're standing on the edge of a platform, your angular momentum is zero. If you start wheeling your arms in a clockwise fashion, your trunk will have to start turning in a counterclockwise fashion so that the total angular momentum of your body is still zero. This is what you want, to get your body to rotate AWAY from the edge. So you rotate your arms in the opposite direction.