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Mimi
climber
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May 26, 2007 - 12:21am PT
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Ed, LEB will be so excited tomorrow morning after seeing your post. I think that's what she was looking for, short of doing a Google search.
Hope all is well. Whatever happened to that piste character? That was an interesting philosophical thread.
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Jaybro
Social climber
The West
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May 26, 2007 - 12:32am PT
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Maybe Gary WAS right?
What about Sasquatch?
Levered a mystery into a cult, I hear.
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Ed Hartouni
Trad climber
Livermore, CA
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May 26, 2007 - 12:33am PT
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Mimi, don't know what happened to piste, his/her posts seem to have disappeared and perhaps the thread (?). This forum provides an ephemeral medium at best.
I'm sure that LEB will have a whole host of questions more... it's her MO, I'll be out climbing in the Valley tomorrow on a one day sneak in and out. Hopefully we'll get done in time to stop by and say "hi" to Tom et al.
Jaybro insider edit: I knew someone would raise that possibility.
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Steve Grossman
Trad climber
Seattle, WA
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May 26, 2007 - 12:39am PT
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Look The Pyramid Is Opening........
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Jaybro
Social climber
The West
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May 26, 2007 - 01:32am PT
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which one?
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Steve Grossman
Trad climber
Seattle, WA
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May 26, 2007 - 01:41am PT
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The one with the ever widening hole.
I had a feeling you were a seeker after that giant rat of Sumatra comment. Have to have something to think about when all the blood's in your head while inverted.
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Ed Hartouni
Trad climber
Livermore, CA
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May 26, 2007 - 06:44am PT
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you can't seem to throw a dead cat around here and avoid hitting a firehead...
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TradIsGood
Happy and Healthy climber
the Gunks end of the country
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May 26, 2007 - 10:23pm PT
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Fer christ's sakes.
Google wikidedia lever. All you needed to know. No waiting.
First hit - duh.
http://en.wikipedia.org/wiki/Lever
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Ed Hartouni
Trad climber
Livermore, CA
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May 27, 2007 - 03:25am PT
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just got back in after a long day...
...the more force you can put on the lever end, the better, probably the best is getting your weight on it. But be careful not to break the handle of your shovel, you'll hurt yourself in the subsequent fall.
It works by the ratio of the lengths because the torques have to balance. It is really just a statics problem. In this case the two torques are the force at the end of the shovel handle times the length to the fulcrum, and the length from the shovel blade to the fulcrum, say F1*r1 and F2*r2.
if these are the same then F1*r1=F2*r2, if you know F1, r1 and r2 you can solve for F2, the force on the thing you are levering out:
F2 = F1 * r1/r2
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morphus
climber
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May 27, 2007 - 11:12am PT
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levers are kewl
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Ed Hartouni
Trad climber
Livermore, CA
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May 27, 2007 - 12:03pm PT
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LEB - Inspite of the virtues you have attributed to me above, I am afflicted with an interest in what science is doing today, and could do tomorrow. So understanding the history of the uses of science (which I might refer to, somewhat cattily as engineering) is not something that I would spend a lot of time on... the history of science, that is another thing all together, I'm talking about the history of applications.
I am sure that the "simple" machines were used in all sorts of impracticle ways, as your suggestion of the rather Rube Goldberg machine of collective levers. The exclusive use of a particular simple machine comes to limits of applicability quickly. Used in conjunction with the other simple machines and you create the machinery that you see around you every day. The definition of the simple machines by physicists is to reduce the analysis of "complex" machines down to understood parts.
As for "rigging" which is the art of moving large objects around, I'd say a physicist has little to add here. I know, as when I was young and working at the accelerator labs we needed to move big stuff around. Now "we" at some point had to include the riggers, whose job it was to move the really big stuff around, like 240 tonne magnets, setting them in the correct place within hundredths of inches. Being a long time "know-it-all" I would come up with all manner of schemes for doing things, very humorous for the riggers as they know the best, safest and most effective ways. I believe that they as a profession have been doing those sorts of "picks" from before written history, without the benefit of a physics analysis... the simple machines, you see, could not have been defined as we do before Newton, and the concept probably came much later than him.
Physicists cannot take credit for any of these marvelous machines, whose story is older than writing, but whose craft was handed down to us from before history.
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morphus
climber
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May 27, 2007 - 12:10pm PT
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Lois (?),
there is no evidence for block and tackle techniques, but we tend to underestimate the skills of our ancestors
log rollers, A-frames etc and lots of workers were undoubtedly used
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morphus
climber
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May 27, 2007 - 12:38pm PT
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Lois, i am NOT Morpheus
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Brutus of Wyde
climber
Old Climbers' Home, Oakland CA
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May 27, 2007 - 12:50pm PT
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LEB --
the "pry bar" mimi was talking about is a long, hardened steel bar specifically designed for what you were doing. Sometimes also called digging bars, they are perfect for this kind of thing. For really big rocks and/or soft soil, you can use two digging bars to great advantage. One bar (laid on the ground or across a hole) serves as a fulcrum, the other as a lever arm. Allows you to adjust both the force you apply to / and the distance you move the big rock without resetting the lever.
I'm sorry to hear that you still don't have the wonder I do when I look at a cell, or cells forming tissue, or the marvelous structures we call organs. And the incredible mechanisms of not only coding information, but of operating that coding in such a way as to produce a living, thinking, reproducing being.
I still feel that same wonder when I consider the "6 simple machines: inclined plane, wheel and axle, lever, pulley, wedge, and screw"... the simple machines which (in the hands of this species) have transformed the face of the planet.
btw -- don't know that you have considered it, but several of these machines are found in our own bodies. Pulley: consider the circular "pulley" ligament that the finger tendon passes through. Levers: look at bone and tendon structure in any vertebrate, and how it moves; look at how the Malleus, Incus and Stapes is arranged to transmit and transmute vibration enroute to the Cochlea. Sorry I don't have my Grey's Anatomy here at work or I'm sure I could come up with other examples.
"most hominids seem to have problems with these simple ideas."
A quote that applies to humans in more cases than not.
Brutus
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dirtineye
Trad climber
the south
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May 27, 2007 - 05:10pm PT
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Most places call it a rock bar. Home depot, 72 inches, point on one end, chisle nose on the other, about 20 bucks.
Don't get a shorter one, those are mostly useless.
Oh yeah, use a smaller rock for your fulcrum, and put the other rock bar to better use.
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dirtineye
Trad climber
the south
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May 27, 2007 - 10:05pm PT
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Collards are so close to cabbage, some collards are called loosley heading cabbage, or something like that.
If you can grow those other brassicas, you can grow collards.
YOu'd better invest in BT, thurgicide, or some other brand of bacterial caterpillar killer, with all that stuff they like to eat in your garden,
Yeha we have a big garden in. only 36 tomato plants though. sounds like you are planting for the critters too, with 68.
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jstan
climber
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May 28, 2007 - 01:58am PT
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LEB
Actually there is a paper describing what you have found. The first author was named Archimedes and like you, he was so amazed he said something like, "Give me a place to stand and I can move the earth." I am not sure he was correct though unless the bar was so long he could use the sun as a fulcrum. That, unfortunately, would have its own problems. If you want the equations for calculating the force type "lever" into google. You will get some nice diagrams too.
What Dirtineye calls a rock bar can be called a prybar or a tunnel bar. I used to call them crowbars though. The tunnel bar is really good for digging holes having well defined walls, putting holes(tunnels) under a wall if you need to get a pipe through, or for breaking rocks. One trick is to wet a rock down thoroughly before breaking it. Water weakens the bonding.
That's the good news. Hold on. I have even better news. Some of the rocks in the walls near your flower bed. Actually came from your flower bed. Next spring you will probably find new rocks in your flower bed. Free. You won't have to pay a dime for them
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dirtineye
Trad climber
the south
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May 28, 2007 - 03:13am PT
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well lois, maybe the bugs have not found you yet. Eventually they will, but until then, enjoy!
Our squash was fine until one year the squash bugs found us, ever since then, it's fight the damned squash bugs.
Soap is good for killing aphids. You can find all sorts of soap spray recipes, just look around.
There are also some organic oils you can use for aphids as well as scale. Neem oil is one, and you can buy it at Lowes now, along with a few other non-toxic to human insecticides.
Crow bars and pry bars usually have an angle on one end. some even have a right angle. Often they have a V for pulling nails and such. Rock bars are just a point on one end and a chisel on the other, and straight.
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hobo_dan
Social climber
Minnesota
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May 28, 2007 - 04:46pm PT
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This is what I teach-Physical Science
Lets assume your blade is 11" and the fulcrum is rigid. With a 66" handle----------66 divided by 11= 6 so you become six times stronger using your shovel to pry. Lets say you way 150 pounds then with no friction you could apply approx 900 poundsof lift with this tool.
I'd get the breaker bar
murf
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