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Q: Bridge Building Competition
Submitted By: michaeljh, 295 days, 3 hours, 14 minutes ago
The bridge building contest I’m entering in consists of putting more and more weight on the model bridge made of pine wood until it goes smashy smashy. You're bridge efficiency is determined by the load it carried before bridge failure divided by its own mass. There is a bucket that hangs down from the bridge where you then put the weights.
The bucket that hangs from your bridge is 2kg and you have a whole mess of weights at your disposal, either 1kg or 0.5kg. Finally, my question: is it good to put the weights in as fast as you possibly can or should you stall just a little bit before putting the next weights in and if so, approximately how long (half a second, a whole second, etc.)?
The bucket that hangs from your bridge is 2kg and you have a whole mess of weights at your disposal, either 1kg or 0.5kg. Finally, my question: is it good to put the weights in as fast as you possibly can or should you stall just a little bit before putting the next weights in and if so, approximately how long (half a second, a whole second, etc.)?
Please try not to post duplicate answers... if you see an answer that you want to post, just add a vote to it and you can add a note as well. Thank You
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Slowly
Submitted By: Raptor235 ( 295 days, 2 hours, 20 minutes ago )
I remember doing the same competition... you basically want to slowly add weight... wait a couple seconds between adding more weight...if you add all the weight at once too much force will break the bridge to pieces.
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0
Slowly
Submitted By: AnotherBrian ( 274 days, 1 hour, 24 minutes ago )
If you add the weight too fast you may get an inaccurate, if slightly in your favor, result. Your bridge design can fail in 2 ways, fast or slow. Let's say you bridge will fail at 10 kg. If it does so slowly you might be able to add some more weight before it fails completely. I would consider this a cheat because the bridge would have failed at 10kg eventually even if you had not added the extra weight. I guess it depends on exactly how you define the failure condition.
You certantly don't want to drop the weight in the bucket, set it in gently so you don't increase the effect of the weight by giving it any unnecessary kinetic energy.
The most accurate way of loading I can think of is to use a water bag instead of the bucket. Put another bucket of water on a stool and run a siphon into the bag. Make sure that you refill the bucket to exactly the same water line and use the same tube, that way the water flow will be exactly the same. The kg/sec increase will equal for all. Tie a slackened rope between the bridge stand and the water bag to catch it after the bridge fails so you don't make a mess.
You certantly don't want to drop the weight in the bucket, set it in gently so you don't increase the effect of the weight by giving it any unnecessary kinetic energy.
The most accurate way of loading I can think of is to use a water bag instead of the bucket. Put another bucket of water on a stool and run a siphon into the bag. Make sure that you refill the bucket to exactly the same water line and use the same tube, that way the water flow will be exactly the same. The kg/sec increase will equal for all. Tie a slackened rope between the bridge stand and the water bag to catch it after the bridge fails so you don't make a mess.