This chapter from Learn GameSalad for iOS offers tips on learning gravity, basic physics, and camera controls when creating an Angry Birds-like game.

Title: Learn GameSalad for iOS: Game Development for iPhone, iPad, and HTML5
ISBN13: 978-1-4302-4356-4
Published: July 2012
Author: David Guerineau
Chapter: “Learning Gravity, Basic Physics, and Camera Controls: An Angry Birds-like Game, Part I”
Publisher: Apress