Subject:
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Re: Physics/Materials geek question
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Newsgroups:
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lugnet.off-topic.geek
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Date:
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Sat, 5 Jan 2002 21:58:37 GMT
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Viewed:
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139 times
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In lugnet.off-topic.geek, Erik Olson writes:
> In lugnet.off-topic.geek, David Goeb writes:
>
> OK, thanks, I will think about keeping slack in the tent when I start
> throwing rocks, that is easier to put in than tin plate.
>
> I'm sorry, I put a rubber eraser "rock" on a postal scale, rounded up the
> metric conversion in my sleepy head and underestimated the volume. The
> "rock" was more like 8 cubic cm and 50g.
>
> So, pick a pebble from 1 to 10g instead.
>
> Now that I have got a book out, lead is 11.34 g/cm3. Calcium carbonate
> ought to be around 1 g/cm3.
Concrete 2.4-ish and so are most non-ore rocks sandstone etc (Gieck 7th ed)
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> The tent needs to be portable to screen a field operator with his LCD
> computer display from flying rocks. I guess I can require 10 cm of headroom,
> too!
That was an offhand worst deformation with minimum attachments guess.
You may need only 5 as 80% of the V will be lost by then anyway.
>
> I'm thinking of how to set up experiments. What is a good way to build a
> rock thrower you can calibrate? Maybe a catapult powered by a dropped weight....
You got it, that would be best for keeping track. Use incremental loads
dropped on c-lever. May have to use two arm solution to keep flat path.
Or maybe: get a truck, lift backend up, skid plate, feed in rocks. :)
(use warning horn and eye protection please)
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> New idea: since the operator is carrying eye protection anyway, get a giant
> goggle for the LCD screen and forget the tent...
>
>
Ear and 'side of jaw' hits are nothing to ignore, yeah eyes are primary but...
I would test 4 or five types of plastic mesh, Bug screens etc. Two layers
of standard plastic bug screen 1cm apart with only upper and lower ties
should stop em cold. Might need replacement after year or two tho.
Best
DaveG
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Message has 1 Reply:
 | | Re: Physics/Materials geek question
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| I've figured out a better way - if the data entry guy stays *in* a truck all day, he has less to worry about.... ties up that truck though. I'm still going to build a catapult though. Going to test it on household materials first... I imagine I can (...) (23 years ago, 6-Jan-02, to lugnet.off-topic.geek)
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Message is in Reply To:
| | Re: Physics/Materials geek question
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| In lugnet.off-topic.geek, David Goeb writes: OK, thanks, I will think about keeping slack in the tent when I start throwing rocks, that is easier to put in than tin plate. I'm sorry, I put a rubber eraser "rock" on a postal scale, rounded up the (...) (23 years ago, 5-Jan-02, to lugnet.off-topic.geek)
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