This document shows how to solve two-dimensional elastic collision problems using vectors instead of trigonometry. This approach is much simpler than using trigonometry. The file is a PDF. If you do not have a PDF viewer, you can download Adobe Reader free.
Here is the main document: 2-Dimensional Elastic Collisions Without Trigonometry
To see these formulas in action, check out the 2-D collision simulator called Bouncescope. This program lets you simulate lots of balls bouncing around and you can customize the mass, velocity, size, and color of each ball.
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©2006 Chad Berchek - all images, text, and software, unless otherwise noted
Clouds at top of page (clouds.jpg) from photo by Oswald Skene / DHD Multimedia Gallery