Physics: out of the comfort zoneThere's only about a week left to get entries submitted for the t-shirt hurling contest, and they entries are coming in. But a traditional problem continues to plague many of the submissions: they're just not going to work! One of the goals of the T-Shirt hurling contest is to get software geeks out of their technical comfort zone and thinking about a totally different area. Building an entry for the contest requires a decent grasp of basic physics, mechanics and materials. Please, when you're working on your entries (and please enter!) think hard about the mechanics. It's often pretty subtle.
For example, Ron Smith, last years winner ended up abandoning his original plan and building something completely different. His original plan seemed really simple and pretty plausible: build a large L shaped structure out of a couple of beams with a pivot where the horizontal and vertical parts join. The horizontal was 4-ish feet long, the vertical was 6-ish feet long. At the top of the vertical was a holder that the t-shirt was placed in. To launch, take a sledgehammer and whack the horizontal. Ought to work, right? It probably could, but it's challenging to get the right materials. The key problem is that when the sledgehammer hits there's an instantaneous force impulse that puts huge stress at the joint between the horizontal and vertical pieces. The device doesn't launch the shirt, it gets torn apart, usually around the pivot. He tried all kinds of materials joints and braces (at F), but none worked well enough.
He gave up on that plan, because the beast just kept ripping itself apart. So he built a Trebuchet. He knew what he was doing (unlike me, when I built one a couple of years before), so his worked like a charm. In this case, his replan worked... But it would still be interesting to see if someone could make it work...
In contrast, the other two entries last year replanned to be more cool... Their original plans were pretty solid, but they feature-creeped into things that were pretty shakey.
|February 7, 2006|