Talk:Lever/Archives/2013

Pronunciation

It needs a note on pronunciation because it is 'lɛvə in American English, 'liːvə in British English.--Hugh7 (talk) 03:20, 23 February 2012 (UTC)

Very good point, it really does. I've just added it. Thank you.  ⊃°HotCrocodile…… + 04:13, 23 February 2012 (UTC)

incorrect math

In the intro it says that the lever allows less force to move something to a greater distance. This is not true. Work=force times distance, so if both force and distance are lowered in the effort, then work must also change. this is impossible, there is no such thing as a work eliminating machine. all a simple machine does is exchange force for distance or vice versa Beefpelican 02:52, 8 February 2007 (UTC) blah blah blah and so on

Agreed. Confusion arose because some people define 'effort' = work = energy. Replaced 'effort' with 'force'. Still not very well worded, but at least it's less ambiguous !--195.137.93.171 10:23, 15 September 2007 (UTC)

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)

Levers

The levers here are correctly labelled. I was wondering if you could tell me what machines (levers) have a mechanical advantage of one.

• The ideal mechanical advantage of a lever is defined as the length between the effort and fulcurm divided by the length between the resistance and the fuThis 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 lcrum, or d_e/d_r. thus, if the effort and resistance are equdistant, then the mechanical advantage equals one. an example of this is a first class lever with the fulcrum in the middle and a weight (the reistance and someone's hand (the effort) at either end. also an old fassioned scale. Beefpelican 02:43, 8 February 2007 (UTC)

The 3rd class lever is incorrectly drawn, for the fulcrum is in the wrong position and renders the lever useless. Since input and output travel in the same direction, the fulcrum should be inverted directly above its existing position in order for the lever to work properly. Try using a broom with the fulcrum positioned as drawn - it just won't work. Now position the fulcrum opposite as drawn - it now sweeps. Kinipopo 09:36, 24 March 2007 (UTC) Kinipopo 09:14, 15 February 2007 (UTC)

For most drawings of third class levers, you need to assume that the fulcrum is actually attached to the plank, while still allowing free rotation. Like a door hinge. Applejuicefool (talk) 17:01, 26 November 2007 (UTC)

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)

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)

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. :-) --Frodet 13:47, 27 September 2006 (UTC)

Yes, I'm sure somebody has performed the math -- it's not like it's difficult. dougmc 23:28, 22 March 2007 (UTC)

Costing a lever of that length might make it a little impractical, not to mention giving him the pivot ... Time doesn't come into it : even if power is limited, he didn't say how far or how fast he would move it !

--195.137.93.171 10:41, 15 September 2007 (UTC)

I think the Archimedes quote should appear on the main page(with a bit of research, of course): It is thought provoking on such a traditionally dull subject. Shutoffyourtv (talk) 07:57, 6 January 2008 (UTC)

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

Examples

i'm not sure if some of the second and third class levers listed are actualy third class, for example the crowbar. this is a first class lever, and is listed as such earlier. if nobody says anything in about a week (casue i'm not an expert) i'll remove the bad examples.

Scissors

Aren't scissors and pliers in the third class?

Arithmetics 05:02, 26 March 2007 (UTC)

15:10, 29 May 2009 (UTC)15:10, 29 May 2009 (UTC)

I would have thought that they are both first class and the tennis racket would be third.

I.D.10-t

Italics are cramming the adjacent text.

It never fails when italics are used it causes a crammed letter issue if used for any emphasis, such as in the word fulcrum for example. I suggest bold, underscore or both be used. --RonEJ 12:29, 28 March 2007 (UTC)

Bottle Opener

Isn't a bottle opener 2nd class and not 1st? The fulcrum is on the end and the load is in the middle.

I think there exist both types. The 2nd class is slightly better ergonomically, but those that are made as 1st class types both use less material, are shorter and thus easier to carry in ones pocket, foldable into a swiss knife or attached to a keyring. My understanding is that the former are generally used in fixed locations such as bars where the ergonomy matters more, but for occasional use as a carryable or swiss knife implement they are usually the latter. I might of course be wrong. -- Cimon Avaro; on a pogostick. 13:59, 9 July 2007 (UTC)

Mousetrap

Besides noting that the bottle opener is still there, I have to question the inclusion of mousetrap as a 3rd class lever. Clearly there are many mousetraps that don't act as levers at all. -- Cimon Avaro; on a pogostick. (talk) 17:44, 29 December 2008 (UTC)

Ok, I modified the visible text of the link to: Mousetrap (Spring-loaded bar type) --HorsemansWiki (talk) 11:09, 31 December 2008 (UTC)

Work = Force x Distance

Under "Theory of Operation", while it is true that Work = force x distance, this distance is not the same as the lever arm (the distance from the fulcrum to the effort or load). I think the relevant principal is the balancing of torques, where the torque is the cross product of force and lever arm, which becomes torque = force x lever arm if the force is perpendicular to the lever.

Adam 71.41.190.154 (talk) 20:18, 14 February 2008 (UTC)

Removing Inappropriate comment

--HorsemansWiki (talk) 23:23, 13 November 2008 (UTC)

Bit (horse)

Some kinds of bit (horse) involve levers; some provide mechanical advantage (ie, not = 1), others don't. Could someone here "sanity check" the article, and related articles on particular kinds of bit, to ensure these bits are not described as violating any law of physics? --Una Smith (talk) 21:36, 28 February 2008 (UTC)

Velocity Ratio

Velocity ratio should be mentioned in this article (or it should have an article of its own and be referenced from here). SpinningSpark 13:02, 30 March 2008 (UTC)

Door is not lever

One of the characteristics used in the definition of lever is that it is used to apply a force to another object. A door is not used like this when it moves. The use of the door moves only the door. Also, doors function i several different ways. A sliding door is even less similar to a lever. --Ettrig (talk) 10:34, 7 October 2008 (UTC)

Curb bit

Thanks for Una for drawing my attention to this topic.

Curb bit always has levers, and when the rein is attached to the curb rein ring and not to the snaffle rein ring, it does provide mechanical advantage (ie, grater than 1 ratio of the forces).

The main question is the measure of the forth applied to he mouth of the horse. The upper end of the lever of the curb bit is held in position by the bridle and the curb chain at the haedstall or cheek ring, which is the real pivot point.

Regarding the mouth of the horse this means that the curb bit operates as a Second-class lever, and not as a first class lever, so I moved it to the group of examples for Second-class levers.

The $F1$ forth is applied at the pivot point mainly to the chin groove, through the curb chain.

The $F2$ forth is applied by the mouth piece to the horse's mouth.

The $F$ force of the rein is applied to the lower end of the shank.

$R1=F1/F$
$R2=F2/F$

Regarding the mouth, the ratio of forthes will be the

• $R2=(cheekorshank)/purchase$

while regarding the chin groove at the lower jaw, the

• $R1=(shankorleverarm)/purchase$

As the

• $(cheekorshank)=(shankorleverarm)+purchase$

it follows that

• $R2=((shankorleverarm)+purchase)/purchase$
• $R2=(shankorleverarm/purchase+purchase/purchase$
• $R2=R1+1$

If e.g.

• $(shankorleverarm)=1*purchase$ than $R1=1$ and $R2=2$
• $(shankorleverarm)=2*purchase$ than $R1=2$ and $R2=3$
• $(shankorleverarm)=3*purchase$ than $R1=3$ and $R2=4$

As it is always true that

• $R1>0$

it is also always true that

• $R2>1$

So it is proven that the mechanical advantage for a curb bit is always greater than 1.

(Note that here we neglected the different angles of the force of the rein and curb chain.)

HorsemansWiki (talk) 20:32, 4 November 2008 (UTC)

Except when the force is applied via the snaffle rein. That is the heart of constant arguments over the Kimberwicke bit. This type of bit has no shank arms and some bits of this type have no slots on the bit D, so that the rein is free to move to the point on the D that provides direct action. The bit belongs to the curb family because it has purchase arms and a curb strap. Some people maintain that it must therefore have a mechanical advantage greater than 1. --Una Smith (talk) 06:25, 10 November 2008 (UTC)

The assignment of fulcrum here is a problem. The top of the purchase arm might be the fulcrum but the bit itself can be the fulcrum. Hence class 1, class 2... Maybe curb bit should go under another section, for "it depends" situations. Else list curb bit under both classes. Where the fulcrum lies depends a lot (entirely?) on the use of the curb chain. Examine photos of bridles with curb bits on Commons

to see what I mean. --Una Smith (talk) 23:08, 10 November 2008 (UTC)

The reason the kimberwicke is classed as a curb is that most designs set the mouthpiece off-center from the ring, and at least if the reins are put into the slots, there is some, albeit not much, leverage. Arguably if the reins aren't in the slot, I can't say what really happens, but the bit mouthpiece is still not centered on the ring. Not a cosmic issue, just a comment. The Kimberwicke is sort of a hybrid design, frowned upon by the purists, so shouldn't have a significant impact on this particular discussion as far as curbs in general go. Montanabw^(talk) 23:14, 10 November 2008 (UTC)

Source, please? I have heard lots of reasons why a Kimberwicke is a curb bit, and this isn't one I have heard before. --Una Smith (talk) 02:24, 11 November 2008 (UTC)

Here is a real basic explanation. Here, for the lever experts, is a page of Kimberwickes, the bottom two are the examples of the "Uxeter" or slotted ring design. Also notice that the bit has a headstall ring, even on the non-slotted ring model. It's OR for me to say that the leverage principle is self-evident from the photo, hence the first link I provided. But this is also not an issue of cosmic importance. The only point is that the kimberwicke looks, at a superficial glance, like a direct pressure snaffle, but it actually is not. Montanabw^(talk) 17:40, 11 November 2008 (UTC)

With regard to the bit being reclassed on the page as a Class II lever, I disagree and after reading through the posts concerning this issue I believe you were correct the first time in classifying the curb bit as a Class I. You have defined a Class II lever as an operation in which input force is put at one end of the work arm, and the fulcrum is at the other, with the output force in between the two. If this is true of a curb bit, then by definition, the output load is somewhere between the end of the shank and the mouthpiece; however, there is no horse or load in between these two. What happens with this bit's use is: (1) the reins are attached at the end of the shank; (2) When the rein is pulled, the mouthpiece rotates in the horse's mouth (you also correctly stated that the fulcrum is the point around which the entire bit pivots). (3) When the shanks reach 45 degrees, the curb chain is engaged, but all that the curb chain does is sit up against the horse's chin groove i.e. create a point where the mouthpiece can't rotate any further. (4) When the curb chain hits the chin groove, the headstall begins to pull down from the horse's poll (the top of his head). This is where the actual output load is generated. If the bit has a ratio of 1:3 pounds of pressure, the additional 2 pounds of pressure aren't exerted by the curb chain/strap. It's actually the headstall that is applying 3 pounds of pressure to the horse's mouth. So with that in mind, to me it looks to me like a Class I, just like a seesaw. The shanks pull on one end with one pound of pressure, which results in 3 pounds of pressure working on the opposite side, with the pivot point in the middle.

So, even if this was what you used to classify it as a Class II (the chain being between the mouthpiece and the shank end, the curb chain is in virtually the same place as the mouthpiece, if not physically higher up the horse's head than where the mouthpiece is resting in the mouth (on the horse's bars). The chin groove makes a right angle with the corners of the horse's mouth. The chain may look like it hangs down, but when it's engaged, it doesn't. I would even go so far as to say that perhaps since the curb chain also rotates in conjunction with the bit, that BOTH the bit AND the curb chain are the fulcrum. I am also having trouble envisioning this type of bit operating as a Class II because as you have diagrammed on the main page, the input and output are both moving in the same direction, simulating an action as in: you're trying to lift a heavy object, so you elevate the opposite end and then pick up your end with the box in the middle. The box moves the same direction as I do. But with a curb bit, clearly the shanks are pulled back while the curb chain and the mouthpiece move in the opposit direction. A Class I lever is the only lever that operates with input effort and output load moving in opposite directions. (I'm not sure if that matters or not.)

Finally, I'm not quite sure how the discussion of the snaffle rein really applies to any leverage discussions. Snaffle, by definition, is the absence of leverage. If it's applying any leverage at all, by causing the mouthpiece to rotate in the horse's mouth, no matter how slight, then it's not a snaffle; it's either a gag or a curb. Curb bits that have snaffle rein rings have broken mouthpieces. The snaffle ring allows the snaffle rein to be attached and for the bit to behave like any other snaffle, such as a D-ring or a full cheek, etc. That doesn't mean that it doesn't have any mechanical advantage, but it does mean it's not a lever. If, by some chance, the a solid mouthpiece bit had snaffle rings and the snaffle rein was attached, when the rein is pulled, the mouthpiece will not rotate. Nothing will rotate. With the type of bit pictured here, it would turn this leverage bit into something more like an incline plane. All that would happen is that tightened reins would slide the bit up the horse's tongue, deeper into his mouth. Releasing the rein would allow it so slide back to where it began. So bringing snaffles into the discussion of leverage is a non-issue, really. --LivingDedGrrl 4:40, 12 November 2009.

Missing word/Vandalism?

"It is important to note the is called the load."

The what? And what's a "maneets arm"? Clayhalliwell (talk) 22:47, 11 December 2009 (UTC)

Adding link of a related article

I just wanna suggest adding link of the article Compound lever to the See Also section. may be useful... thanks. — Preceding unsigned comment added by 2.178.102.2 (talk) 10:02, 12 September 2012 (UTC)