 | | Physics/Materials geek question —Erik Olson
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| | | I know there is a difference between the yield strength of a material under load, and its strength under projectile impact. What I'm wondering -- and this is a little like our "going to Mars" questions -- is to estimate how much abuse will some (...) (23 years ago, 5-Jan-02, to lugnet.off-topic.geek)
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| | | | | Re: Physics/Materials geek question —David Goeb
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| | | | (...) Did you want full FEA on that or will rough back of the hand range do? Oh and more to the point What are those rocks made of to get that mass? Lead works out as less than 20/cm3... Actually the distance between tie points and overall stress (...) (23 years ago, 5-Jan-02, to lugnet.off-topic.geek)
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| | | | | | Re: Physics/Materials geek question —Erik Olson
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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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| | | | | | Re: Physics/Materials geek question —David Goeb
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| | | | (...) Concrete 2.4-ish and so are most non-ore rocks sandstone etc (Gieck 7th ed) (...) 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. (...) You got it, that (...) (23 years ago, 5-Jan-02, to lugnet.off-topic.geek)
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| | | | | | Re: Physics/Materials geek question —Erik Olson
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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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| | | | | | Re: Physics/Materials geek question —Jeff Jardine
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| | | | (...) A gravity-powered catapult is called a trebuchet. This site is a good place to start: (URL) are lots of links to other sites with plans, etc. I made a small one last summer, with a beam ~50cm long. It can fling a ~10g rock over 50m. Much fun! (...) (23 years ago, 7-Jan-02, to lugnet.off-topic.geek)
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| | | | | | Re: Physics/Materials geek question —Christopher Tracey
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| | | | (...) <snip my new summer project ;) > Trebuchet is also my favorite MS font. I just got done designing a flyer for a conference using this for the logo. Now I know where the name comes from. thanks! -chris (23 years ago, 8-Jan-02, to lugnet.off-topic.geek)
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| | | | | | Re: Physics/Materials geek question —Erik Olson
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| | | | K.K. Quah has designed a Lego trebuchet. (URL) (23 years ago, 9-Jan-02, to lugnet.off-topic.geek)
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