walkingstyx wrote:Yeah, K'nex and final devices rarely mix well. Also, you might want to try increasing the weight at the bottom to increase the duration. It won't change the period, but it will give it more inertia and decrease the damping factor. You could also try pulling it back a greater angle to start with. Thirdly, when you build it with wood use a bearing or lots of lubricant or something else to decrease friction.
Bogoradwee wrote:seeing as i haven't tried a pendulum, i can't entirely answer your pendulum question, but i can imagine that they could have attached some thing that the pendulum's path would line up with and it could have markings, allowing specific regions to be specific tenths of seconds.
Nope, you're not allowed to use a calculator at all for the first part of the competition. It's really dumb in my opinion--if you can use an electronic balance for a water clock, why can't you use a four-function calculator for the pendulum? It's not that difficult to just multiply it out, though, in the minute you get between launches. Just make sure you double check.Gooblah wrote:1) Would one be allowed a calculator, if an irregular period (as invariably would happen) existed for counting purposes?
Yeah, it is. You can get pretty accurate, though, because of the way period is measured. Say you've got a pendulum with a period of exactly one second. (It's a little unrealistic to calibrate something so precisely, but it would be about 10 inches long.) That means that the outswing is half a second, and the backswing is half a second. You can easily subdivide these in half, because you can see if it's passed the equilibrium position or not.Gooblah wrote:2) How would one measure tenths of a second with a pendulum? It seems like one would be just guessing at some point...
You could definitely experiment with something like this, but I would say don't bother. You just won't have time to make such an intensive calculation in a minute. I wish you could bring a chart or something, but you'd have to bring one for each angle--that's like 45 of them. Spending some quality time with your pendulum will be much more beneficial in the long run. You'd be surprised how accurate you can be once you get to know it.Bogoradwee wrote:seeing as i haven't tried a pendulum, i can't entirely answer your pendulum question, but i can imagine that they could have attached some thing that the pendulum's path would line up with and it could have markings, allowing specific regions to be specific tenths of seconds.
Sir_L_Jenkins wrote:Unfortunately, it takes time to master time. Unless you have a fancy ocarina, you may be out of luck.
However, if you're looking for some quick resources, wikipedia's good for quick binder making, and maybe some physics review of some mechanics. Otherwise just look at the topics in the rules and search around for that stuff. The official SO site also has some decent resources
SRBHAR01 wrote:My invitational test had physics problems like velocity and acceleration.. Which was stupid plus we had to wait 1 hour for the event started so i missed my 2nd event .
Paradox21 wrote:We had our regional competition on Saturday in Minnesota (not the most competitive state) and I got to see the raw scores for the event and I was amazed at the scores for the time trials. There were at least 5 teams within a 48/50 for the trials. The deciding part really seemed to be the test. Out team got 5th in the time trials with a low 48 score (48.3 I think) but got 1st overall because we did well on the test. As far as I know all of the designs were relatively simple pendulums.
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