Talk:Lever
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[edit] Classes
I'm unsure, but it appears to me that the description of the 1st and 2nd class levers are switched around. The book im looking at (American School Physical Science Study Guide) has these levers listed as the opposite. Basically, the 1st class lever on wikipedia is listed as 2nd class in book, and 2nd class on wikipedia is listed as first class in the book. If anyone can clear this up that'd be great. Thanks!
My twelve-year-old daughter says that they are not mixed up in this article.
Is there a class like class 1 where the effort is closer to the fulcrum than the load or is that still concidered class 1? Tsinoyboi 11:15, 22 September 2006 (UTC)
[edit] Archimedes screw
This sentence: Archimedes also invented Archimedes' screw, which was used to draw water from a lake or river, although this falls under the screw category. has nothing to do with levers - should it be removed? —The preceding unsigned comment was added by 203.59.154.246 (talk • contribs) .
- Quite right. I have done so. Anyone interested in other work by Archimedes can check his article. -- Ec5618 18:04, 1 February 2006 (UTC)
[edit] Levers
The levers here are correctly labelled. I was wondering if you could tell me what machines (levers) have a mechanical advantage of one.
[edit] The Fulcrum
Does the "plank" need to sit ontop of the fulcrum to be a lever? Or can the fulcrum/pivot go through the plank and still be a lever? I'm curious to know if a two-prong propeller counts as a lever. 205.174.22.28 01:46, 23 July 2006 (UTC)
The fulcrum is the pivot point, so it can go through such as in scissors. I don't know what you mean by two-prong propellers. propellers in general act more like wheels (though, wheels and gears work on the same principle as levers), but the pushing air part might be more of either Screw (simple machine) or Airfoil or both. Tsinoyboi 11:00, 22 September 2006 (UTC)
[edit] More examples
Maybe it should be included how Engineering vehicles use levers along with hydraulics and other simple machines. Perhaps even just saying that in general could be enough. Cranes, for example, use one or more class of lever. I aded engineering vehicles in see also. should that be moved or removed? Tsinoyboi 11:22, 22 September 2006 (UTC)
[edit] Archimedes' quote
Archimede is supposed to have said:
- Give me the place to stand, and I shall move the earth.
While this may be theoretically true, has anyone actually performed the maths to figure out the practicality with respect to time spent exercising a certain amount of energy, etc.? Just curious. :-)
[edit] add an example
add a simple example of calculating lavarage formulat near to the image is bad the formula should be bigger. and a proof of the direvation from newton law
