You don't actually need any fancy software to see what's going on if you've mastered the fine art of free body diagrams: http://www.tjradcliffe.com/?p=1374 http

You don't actually need any fancy software to see what's going on if you've mastered the fine art of free body diagrams: http://www.tjradcliffe.com/?p=1374 http://www.tjradcliffe.com/?p=1374 (not related to skateboards, but those damned wobbly suitcases). And the advantage of simple free body diagrams is they are amenable to relatively simple models, frequently involving simple harmonic motion: http://www.tjradcliffe.com/?p=1410 http://www.tjradcliffe.com/?p=1410 These are teachable skills, and while it's great we have software to help us out, I'm a sufficiently aged crustacean to see the value in learning to do these sorts of analyses formally, by observation and inference.