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Model Forum / General / Models / November 2007Exam question assistance please
Could someone tell me the correct answer to this test question please. Sorry about the poor picture quality. Question is "Which girder will take the most weight, A. Equilateral angles, B. Obtuse angles, C. Acute angles. Picture is at :- http://www.mediafire.com/imageview.php?quickkey=0tymfcn0aal&thumb=4 Thanks, Phill. > Could someone tell me the correct answer to this test question please. > Sorry about the poor picture quality. [quoted text clipped - 6 lines] > Thanks, > Phill. I would have thought A. In B the struts are very rigid but there is a long gap between them which means the lower beam can buckle. In C there are short gaps so the lower beam is less likely to buckle but the struts are weaker. A seems intuitively the best compromise but I think it might depend on the thickness and strength of the beams.  SignatureDave Baker - Puma Race Engines > Could someone tell me the correct answer to this test question please. > Sorry about the poor picture quality. [quoted text clipped - 5 lines] > Thanks, > Phill. dont know what they are supposed to mean ... if they are talking triangles transfering weight above them to floor ... the multitriangle set-up is best ... all the best.mark > if they are talking triangles transfering weight above them to > floor ... I think, because it is a girder, that it is supported on the left and right end and takes a load on top of it. Like a bridge. Nick SignatureThe lowcost-DRO: <http://www.yadro.de> > > if they are talking triangles transfering weight above them to > > floor ... [quoted text clipped - 6 lines] > The lowcost-DRO: > <http://www.yadro.de> in that case then ...it would be "c" which is the best .because it has the most metal in it . if it was a case of which one could be most economically made, it would be "b" if it was a case for which one was best compromise for price and load carrying it would be "a" wonder what drug exam compiler of questions is on ..he's far removed .if you have only the choice of answering a,b, or c all the best.mark mark Wrote: > > I think, because it is a girder, that it is supported on the left an > right [quoted text clipped - 4 lines] > > The lowcost-DRO: > > <http://www.yadro.de> Is there significance in the (faint)arrow to the left of each diagram with indecipherable writing attached? Is it meant to be the direction of load? if so, then your assumption is wrong, this girder is resisting en loads, in which case the choice of a) is more rational. Robi -- rss >> > if they are talking triangles transfering weight above them to >> > floor ... [quoted text clipped - 10 lines] > in that case then ...it would be "c" which is the best .because it has > the most metal in it . You might want to rethink that before the examiner hears or he'll be after you for the remedial geometry class I'm afraid. SignatureDave Baker - Puma Race Engines > "mark" <aboard_epsilon@yahoo.com> wrote in message >> in that case then ...it would be "c" which is the best .because it has >> the most metal in it . > > You might want to rethink that before the examiner hears or he'll be after > you for the remedial geometry class I'm afraid. PS. Here's a clue. Why is the area of any triangle, symmetrical or otherwise, always 1/2 base x height? SignatureDave Baker - Puma Race Engines > > "mark" <aboard_epsi...@yahoo.com> wrote in message > >> in that case then ...it would be "c" which is the best .because it has [quoted text clipped - 7 lines] > -- > Dave Baker - Puma Race Engines the exam question is flawed ... if you wanted to show differences he should of set out out with the same amount of metal spars doing the their thing in each diagram .. c has a multitude of spars ...despite being all at the wrong angle it will win over the others ...because of the shear amount of metal in it . so stuffy examiner does not know how to set out questions in my opinion. you just cant answer that one ...if you have the choice of leaving it and answering another question instead ...i would .. all the best.mark >the exam question is flawed ... >if you wanted to show differences [quoted text clipped - 13 lines] > >all the best.mark Mark - ...and you would (rightly) fail the test. Firstly, the "amount of metal" is the same in each case. Dave already tried to point that out to you, but you weren't paying attention. Sum the areas of the triangles in each diagram and you will find they are the same, so the "amount of metal" is the same in each case. My guess is that was entirely deliberate on the part of the examiner. Secondly, it isn't how big it is, but how you use it. Take a trivial example - a round bar of a given weight of metal per unit length will support a smaller load than a round tube of the same weight per unit length. So the important issue isn't the amount of metal in the three different designs but the way that metal is distributed. Regards, Tony > >the exam question is flawed ... > >if you wanted to show differences [quoted text clipped - 36 lines] > > - Show quoted text - well the site isn't working now so i cant check out what you said tony you're saying same amount of metal used in all three diagrams ... didn't look like it to me and cant check now but will take your word on it and not argue any longer i know all the principles but this just says to me corrugated cardboard. all the best.mark And Barnes Wallis and the Wellington Bomber! Or for the really wheelies-- the bird cage construction on cars. Mark is usually right-- cornflake packets or A HOUSE OF CARDS! Well? >> > "mark" <aboard_epsi...@yahoo.com> wrote in message >> >> in that case then ...it would be "c" which is the best .because it has [quoted text clipped - 14 lines] > he should of set out out with the same amount of metal spars doing the > their thing in each diagram .. He did. That was in fact the whole point of the question! > c has a multitude of spars ...despite being all at the wrong angle it > will win over the others ...because of the shear (sic) amount of metal in > it . Well don't say I didn't try to give you a hint. The spars consist of triangles, all facing the same way and with their bases touching each other. To find the total area of metal in the triangles in each of the three cases. Area of each triangle = 1/2 base x height. As the bases touch then the sum of the base length is the length of the beam - in all three cases. The height is the depth of the beam - in all three cases. Therefore the total area of metal = 50% of the cross sectional area of the beam - in all three cases. It doesn't matter what shape the triangles are in such an arrangement. The area will always be half that of the beam. The triangles can even be non symmetrical without affecting the solution and in fact it still doesn't matter if they aren't all the same shape. SignatureDave Baker - Puma Race Engines > >> > "mark" <aboard_epsi...@yahoo.com> wrote in message > >> >> in that case then ...it would be "c" which is the best .because it has [quoted text clipped - 36 lines] > -- > Dave Baker - Puma Race Engines I'm not counting them as complete triangles because top and bottom you got beams ... this is supposed to be a girder ...not a bunch of triangle sections stitched together I'm counting them as diagonal spars ... on "c" you have 14 diagonal spars on "a" you have 8 diagonal spars. the top and bottom of the triangles is already there in both cases as the beams ... so you got two girders to compare one with 8 spars ... and one with 14 spars . welded to the top and bottom beams . thats how i see it . all the best.mark > I'm counting them as diagonal spars ... The triangles were solid. Question during the test: "Sir, are these triangles *really* solids?" And if the answer is "Yes!", try to look as stupid as possible. :-) Nick SignatureThe lowcost-DRO: <http://www.yadro.de> >> > he should of set out out with the same amount of metal spars doing the >> > their thing in each diagram .. [quoted text clipped - 35 lines] > > I'm counting them as diagonal spars ... Well if you don't want to answer the question that was actually set there's probably little left to discuss. SignatureDave Baker - Puma Race Engines > > "Dave Baker" <D...@Dave.com> wrote in message > [quoted text clipped - 29 lines] > > all the best.mark It's related to the second moment of area, no? -- Nige Danton >It's related to the second moment of area, no? I thinks thats it exactly. Isn't it bd squared over 12 or something like that? Peter > Could someone tell me the correct answer to this test question please. > Sorry about the poor picture quality. [quoted text clipped - 5 lines] > Thanks, > Phill. C Acute angles. > Question is "Which girder will take the most weight, A. Equilateral > angles, B. Obtuse angles, C. Acute angles. Puzzling! I'm inclined to say that all 3 take the same load. Arguments: * the area of the triangles is the same for all 3 solutions * The upper belt is compressed, and all 3 solutions cover the full length of the upper belt * the lower belt is expanded, no buckling * the cross-section of the triangles in the neutral line (where you have the biggest shearing forces) is the same. The reason why I-beams that are cut, shifted and re-welded (that honey-comb pattern) look more like A) is to reduce the length of cut and to get a beam as high as possible. I might be corrected. How many points did I get? Nick SignatureThe lowcost-DRO: <http://www.yadro.de> Well, I am a at least not alone. I thought C. because of the fact that the triangles sides are more vertical, so less side stress, but the answer paper says A. I would really like to get a professional engineers opinion on this one. Thanks for the input. It is interesting. Phill. >> Question is "Which girder will take the most weight, A. Equilateral >> angles, B. Obtuse angles, C. Acute angles. [quoted text clipped - 18 lines] > How many points did I get? > Nick from Phill > Well, I am a at least not alone. I thought C. because of the fact that > the triangles sides are more vertical, so less side stress, > but the answer paper says A. > I would really like to get a professional engineers opinion on this one. > Thanks for the input. It is interesting. I wasn't going to offer an opinion because (to me is seemed so simple) but the variety of anwers has amazed me. Without looking at the diagrams I deduced that the Equilateral had to take the most weight since the virtical and sideways stresses will be equal and be directed down the length of the side of the triangle - putting the material in compression - with the obtuse the vertical stress component will be greater than the sideways component and in the acute the sideways stress will exceed the vertical. J (nearly failed HND mechanical engineering but was reassessed ;) ) G Well, you only "nearly" failed. I haven't even sat the test, so I'll take your word for it. Thanks for your help. Phill. > from Phill > [quoted text clipped - 17 lines] > > J (nearly failed HND mechanical engineering but was reassessed ;) ) G >from Phill > [quoted text clipped - 17 lines] > >J (nearly failed HND mechanical engineering but was reassessed ;) ) G Another way to look at is the load distribution per unit area. If we are assuming that the amount of material in the triangular supports is the same in all cases, and the load is evenly distributed across the top surface, then there will differing apex loadings at the lower surface. The top surface support is across the base of the triangles and will concentrate the load across 2, 4, or 7 points on the bottom. Therefore there should be a lower force per area with the acute triangles. As such, perhaps the failure mode would be on the lower beam, rather than the triangulation? Peter >Well, I am a at least not alone. I thought C. because of the fact that >the triangles sides are more vertical, so less side stress, [quoted text clipped - 5 lines] > >Phill. I'm a professional engineer, unfortunately not a mechanical one, so I don't really have a clue. :) I'd suggest that in reality, if the weight was evenly distributed, there would be no difference in their load bearing capability. The bigger issue is the load bearing capability of the ground it is resting on - those pointy bits could do no end of damage! Sorry, I told you I wasn't a mech. eng. Mark > Sorry, I told you I wasn't a mech. eng. I am, and I don't understand the question. SignatureCharles Lamont >> Sorry, I told you I wasn't a mech. eng. > >I am, and I don't understand the question. So am I and I think the question is appallingly badly set. How is the load applied, how is the girder supported and how is it constructed? As it stands it may as well have read 'Are apples better than monkeys?' or some such sureal gibberish. Richard MIMechE In article <1h7nj3d0is45ta2cjdnp850nh15s8dsu3s@4ax.com>, Richard <sharkface-pilot@toucansurf.com> in uk.rec.models.engineering wrote: >>> Sorry, I told you I wasn't a mech. eng. >> [quoted text clipped - 6 lines] > >Richard MIMechE Sadly this sort of test question is becoming all to common. Acceptable in a Sunday night pub fun-quiz for a prize of a few pints of beer, but not if the test is to relevant to employment, etc. I've seen some horrors in the amateur radio test questions, electricians' trade test stuff and even in the driving licence written test. Intentionally, no comment on recent A-level maths and science papers, it would be very bad for my blood pressure. Regards, David P. C.Eng, MIEE (or whatever the IEE calls itself now.) > I'm inclined to say that all 3 take the same load. Still am convinced of my answer*). But that question is quite stupid, because girders don't look that way. If the triangles weren't solid (but tubes) it wouldn't be a girder but a structural frame**). And then, a) would be right. *) with one assumption on how it is supported. Can argue in detail if you want. **) Looking in the dictionary, I see that a structural bridge is called "girder bridge". I thought that "girder" is an I-beam. Don't you distinguish between the two or is my dictionary wrong? Nick SignatureThe lowcost-DRO: <http://www.yadro.de> >> I'm inclined to say that all 3 take the same load. > [quoted text clipped - 12 lines] > > Nick I think they are using the term as a structural element, it can also be a structure in itself though. > I think they are using the term as a structural element, it can also be > a structure in itself though. So girder can be an I-beam, but also be something more general? To be more specific, is "structural girder" a valid expression? And an I-beam zigzag-cut/shifted/re-welded is called a honeycomb beam/girder? Nick SignatureThe lowcost-DRO: <http://www.yadro.de> >So girder can be an I-beam, but also be something more general? ...Of course there was the one about the Irish labourer that was asked the difference between joist and girder...he said "Joist wrote Ulysses and Grider wrote Faust"...<G> Regards, Tony In article <5q2rm4Ftitr1U1@mid.individual.net>, Nick Mueller <muellernick@gmx.de> in uk.rec.models.engineering wrote: >So girder can be an I-beam, but also be something more general? >To be more specific, is "structural girder" a valid expression? >And an I-beam zigzag-cut/shifted/re-welded is called a honeycomb >beam/girder? I was taught "castellated beam/I-beam/RSJ". Regards, David P. I am flabbergasted. I am applying for a job as a Trainee Locomotive Driver, and this is one of the Sample Test questions sent to applicants to familiarize them with the entrance examination. (This by the company that runs the rail system in this state) If Engineers can't understand the question, what hope have hope-fulls like me got? Another question that would have to fall into the category of "Very Poorly Written" surely:- The question is, "Which gate is the strongest?" It is at:- http://www.mediafire.com/imageview.php?quickkey=dpsljlwgy93&thumb=4 I would suggest that both gates B. and C. are identical in strength, as they are identical in construction, only the method of mounting is different. However, that is not what the question is in my view. Another point is that a gate is presumed to be for the purpose of keeping something in or out. This being the case, the direction of force requiring strength would be presumed, in the absence of contra-indication in the question, to be parallel to the ground and at right angle to the face of the gate. This would also result in A. & B. being equal in strength would it not? I would suggest that the question, based on the given answer, should have read "Which gate is mounted in the strongest way?" The answer sheet providing their logic is at:- [Question (8)] You will need to click on LARGE at mediafire:- http://www.mediafire.com/imageview.php?quickkey=6tvb0lmnmn9&thumb=4 It also gives their logic to the girder question (8) Phil, >Another point is that a gate is presumed to be for the purpose of >keeping something in or out. This being the case, the direction of force >requiring strength would be presumed, in the absence of >contra-indication in the question, to be parallel to the ground and at >right angle to the face of the gate. This would also result in A. & B. >being equal in strength would it not? I can't respond to your particular points since I can't raise the image on the web site, but one major force present in a gate is its own weight. In a long gate, like a farm gate, the moment of the weight about the hinges can be significant. So I believe that the preferred way of building a gate is to place the diagonal struts(s) so that it(they) are in compression rather than tension under the force of the weight. Jim. >Phil, > [quoted text clipped - 12 lines] >that it(they) are in compression rather than tension under the force >of the weight. Depends on how the gate is made. An old fashioned 5 bar all timber gate with dowelled, morticed & tenonned corner joints would have a compression brace - no need to tie the brace to the frame corners. A welded metal gate frame would have a thin tension brace welded at the corners. Ledgered and braced sh*t-house doors are often hung upside down, the braces should be in compression, transferring the load to the ledgers. If you have one hung wrong, with a corner dragging on the floor, the easy fix is a tension brace - a loop of steel wire between top hinge side and bottom lock side, fixed by two bolts, then tighten using spanish windlass method and secure. Regards, David P. On Thu, 15 Nov 2007 07:28:53 +0000, Jim Guthrie wrote, in impeccable English,.. >Phil, > [quoted text clipped - 12 lines] >that it(they) are in compression rather than tension under the force >of the weight. Quite. And it's surprising just how many newly made wooden gates you find the wrong way up. These are usually to be found at "wildlife" reserves complete with over elaborate hinge and latching devices, most of which fail to work as designed due to poor installation/tuning/maintenance. Lovely wood though. SignatureRay The volume of a pizza of thickness 'a' and radius 'z' is given by pi*z*z*a. > I am applying for a job as a Trainee Locomotive Driver, and this is one > of the Sample Test questions sent to applicants to familiarize them with > the entrance examination. (This by the company that runs the rail system > in this state) Oh sh*t! Now this is really stupid. The question wasn't asked well (leaving out constraints) and the construction shown wasn't very clever (none of the three) and then they ask that a loco driver? I bet they didn't give an explanation why a) might be the solution. Try to make the pilot's exam, their questions should be more logical. :-) Nick SignatureThe lowcost-DRO: <http://www.yadro.de> > Try to make the pilot's exam, their questions should be more logical. :-) > > Nick You would have to hope so....:-) >I am flabbergasted. > Another question that would have to fall into the category of "Very Poorly [quoted text clipped - 8 lines] > they are identical in construction, only the method of mounting is > different. However, that is not what the question is in my view. Clearly B is the strongest. A has no diagonal bracing at all and C has the brace running in the wrong direction. SignatureDave Baker - Puma Race Engines > >I am flabbergasted. > > Another question that would have to fall into the category of "Very Poorly [quoted text clipped - 14 lines] > -- > Dave Baker - Puma Race Engines its another stupid question, strength depends on what use the gate is put to .. but as a farm gate ... C is how most of them are made ....and would be the answer examiner is looking for . C is least likely to buckle or sag when someone swings on the end of it and is economical compromise over metal used. on c the brace acts like suspension bridge where as A would survive a charging rhino, full on, into it.better than C...it has not the same abilities to survive someone swinging on it...or the test of time over sag. B is just bad design with brace running wrong way. no rhinos in the uk .....so C is best. all the best.mark > > >I am flabbergasted. > > > Another question that would have to fall into the category of "Very Poorly [quoted text clipped - 39 lines] > > all the best.mark An interesting discussion and a good example of how the practical doesn't always agree with the theoretical. Years ago when wooden 5 bar gates were made of real wood in reasonable cross sectional areas the brace was (from memory) invariably in compression. Nowadays with gates made from paper thin sections, putting them in tension stops any droop caused by bowing sideways of the invariably too thin cross brace or unseasoned wood. However if you look at the current best gates when the brace is in tension the hinge post is usually extended upwards and the suspension point of the brace is above the top rail thus providing some additional support for the top rail as well. Alternatively they are triangulated with the first half of the gate span braced in compression and the outer half in tension. Just observations of the practical application, I'm not getting involved in the boring theoretical stuff. Of course it does highlight the crap that is set as exam questions these days; perhaps it is to find out if the train driver knows which one to aim his train at in an emergency - they have got steering wheels on trains haven't they :-))) Keith <snip> >Years ago when wooden 5 bar >gates were made of real wood in reasonable cross sectional areas the >brace was (from memory) invariably in compression. Because mortice & tenon joints are not particularly strong in tension, but work well in compression. Richard >>Years ago when wooden 5 bar >>gates were made of real wood in reasonable cross sectional areas the >>brace was (from memory) invariably in compression. > >Because mortice & tenon joints are not particularly strong in tension, >but work well in compression. However, with modern farm gates being made from welded steel tube, it probably makes more sense for the brace to be in tension. Regards, Tony >>>Years ago when wooden 5 bar >>>gates were made of real wood in reasonable cross sectional areas the [quoted text clipped - 5 lines] >However, with modern farm gates being made from welded steel tube, it >probably makes more sense for the brace to be in tension. Interestingly, having just come back from a weekend in rural Scotland, modern welded tube farm gates don't have any diagonal bracing at all. They seem to get enough stiffness from the welded joints. Regards, Tony > Interestingly, having just come back from a weekend in rural > Scotland, modern welded tube farm gates don't have any diagonal > bracing at all. They seem to get enough stiffness from the welded > joints. Scottish farmers being what they are the stiffness doesn't come into it - the cost does:-)) >>> I am flabbergasted. >>> Another question that would have to fall into the category of "Very Poorly [quoted text clipped - 36 lines] > > no rhinos in the uk .....so C is best. You have some damn big Hamsters :-) > all the best.mark Mark, I was as sure as you that the answer they were looking for was C but in fact they want B for the answer. I agree that B is hung incorrectly. All the gates on my hobby farm are hung like B and most in the area are also. The thing is, the question doesn't ask which is hung properly, it asks which gate is the strongest, and I still say B & C are identical. If you take them both off the hinges and away to a testing facility, they are going to come up the same under any strength test. Agreed? or not? If I don't pass this test, (It is today) then I am going to challenge the validity of the test questions. Cheers, Phill. I should add that these are quick-quiz type questions, we are given 30 seconds for each one. :-) Cheers, Phill. > >>> I am flabbergasted. > >>> Another question that would have to fall into the category of "Very Poorly [quoted text clipped - 56 lines] > > - Show quoted text - Sounds like you're going to have to put your Maxwell Hutchinson head on when answering these questions ... bite the bullet ....and just give answers what they want. no wonder bridges are failing . stadium roofs are collapsing under weight of snow. if they design things through theory and not look at every eventuality . all the best.mark > Mark, I was as sure as you that the answer they were looking for was C > but in fact they want B for the answer. [quoted text clipped - 6 lines] > If I don't pass this test, (It is today) then I am going to challenge the > validity of the test questions. Imagine the gates with all the members removed except the two running from the top and bottom hinges. In the case of B that's a diagonal running upwards and meeting a horizontal and in C vice versa. Those two are the primary elements of the gate and in fact could be a gate on their own in some cases. Now imagine a person swinging on the end of the gate. In the case of B the horizontal member has almost zero strength on its own but as it tries to rotate it transmits the force into the diagonal putting it into almost pure compression. The diagonal is bracing upwards against the downwards force being applied to it. The horizontal is being put into tension at the same time which makes it very strong. Now do he same with C. As the diagonal tries to rotate it also tries to pull the horizontal down with it. The force isn't being transmitted into the horizontal at anything like such an advantageous angle. It is also going into compression to some extent but is experiencing a greater bending moment than the upwards diagonal in B. The question seems perfectly fair to me. All exam questions require the candidate to make certain common sense assumptions and it's reasonable to assume a gate isn't being designed to resist upwards forces. It has to withstand its own weight and anything or anyone swinging on it. B is clearly the much stronger design. Yes it's the same gate as C but hung the other way up but that's the whole point isn't it? Doing things right instead of wrong. SignatureDave Baker - Puma Race Engines >> Mark, I was as sure as you that the answer they were looking for was C >> but in fact they want B for the answer. [quoted text clipped - 32 lines] > the much stronger design. Yes it's the same gate as C but hung the other way > up but that's the whole point isn't it? Doing things right instead of wrong. Thanks for that great explanation Dave. It makes sense to me at first reading, however, can I put this to you. Using you idea of just the two main elements, ...assume a very very long gate made of material that is too light for the job. In gate B the diagonal would have a slight bend in it because of its own weight, then someone swings on the end and the diagonal gets bent further and fails. In gate C, the diagonal would have the same bend from its own weight, then someone swings on the end and the diagonal will straighten out and all is well. Am I wrong in this assumption? The only doubt I have about my reasoning is that if this scenario was that heavy enough material was used and the gates were tested to destruction, wold the diagonal under compression outlast the diagonal under tension? In other words, does it take a greater force to concertina a given tube (or rod) than to stretch it to breaking point?? Cheers, Phill. > Using you idea of just the two main elements, ...assume a very very long > gate made of material that is too light for the job. In gate B the [quoted text clipped - 4 lines] > then someone swings on the end and the diagonal will straighten out and > all is well. Am I wrong in this assumption? Sounds ok :) > The only doubt I have about my reasoning is that if this scenario was > that heavy enough material was used and the gates were tested to > destruction, wold the diagonal under compression outlast the diagonal > under tension? In other words, does it take a greater force to > concertina a given tube (or rod) than to stretch it to breaking point?? Given that a steel tube or bar is always going to be slightly distorted from manufacture, I think it would be /far/ stronger in tension (gate C best). But a wooden gate would be stronger in compression as it pushes the joints together (gate B best). Just to stir the pot: the hinges are offset a bit from the top & bottom cross-beams of the gate, so I reckon it would probably bend or break close to them, 'cos they're fulcrums. Guy >>> Mark, I was as sure as you that the answer they were looking for was C >>> but in fact they want B for the answer. [quoted text clipped - 45 lines] > someone swings on the end and the diagonal will straighten out and all is > well. Am I wrong in this assumption? In gate C it would also be the horizontal that would be bent under it's own weight and would fail further with extra weight on it. In either case type B would be stronger. > The only doubt I have about my reasoning is that if this scenario was that > heavy enough material was used and the gates were tested to destruction, > wold the diagonal under compression outlast the diagonal under tension? In > other words, does it take a greater force to concertina a given tube (or > rod) than to stretch it to breaking point? Relatively thin struts will always be stronger in tension than compression but any braced structure like this will rely on compression somewhere and that's where it will fail. With wooden gates the upwards diagonal needs to be fairly sturdy to take the compression loads. The rest can be weaker as they just provide extra bracing. In fact most of the rest of the gate other than the two main members is only there to completely close off the opening in question. To an extent the lighter they are the less strain the gate is under from its own weight. All the parts underneath the diagonal are only there for the ride. The bits above the diagonal help brace it. SignatureDave Baker - Puma Race Engines > Relatively thin struts will always be stronger in tension than compression > but any braced structure like this will rely on compression somewhere and > that's where it will fail. That's also why you need to go to suspension bridges for very long spans. Braced structures operating in compression fight a losing battle against their own weight eventually. SignatureDave Baker - Puma Race Engines > The answer sheet providing their logic is at:- [Question (8)] You will > need to click on LARGE at mediafire:- > > http://www.mediafire.com/imageview.php?quickkey=6tvb0lmnmn9&thumb=4 > > It also gives their logic to the girder question (8) What an appalling set of answers, this is an 'engineering' test set by someone who doesn't have the first clue about basic engineering principles. You've got to love question 4...... "A cog turning clockwise, will turn a cog next to it anticlockwise" Ok so far. "Cogs connected with a straight belt will move in the same direction" They're not bloody cogs then are they!! They're pulleys! > Could someone tell me the correct answer to this test question please. > Sorry about the poor picture quality. [quoted text clipped - 6 lines] > Thanks, > Phill. I would say B. Own weight is less, so it can take op more weight, assuming all three are evenly strong. Dirk > Could someone tell me the correct answer to this test question please. > Sorry about the poor picture quality. [quoted text clipped - 6 lines] > Thanks, > Phill. ...finally got to look at the two questions. There simply isn't enough info given to be able to answer the questions, regardless of how long you are given. I suppose that was the emerging consensus. Can you tell us who set these 'questions'? (The answer page won't come up) Peter >> Could someone tell me the correct answer to this test question please. >> Sorry about the poor picture quality. [quoted text clipped - 12 lines] > Can you tell us who set these 'questions'? (The answer page won't come up) > Peter Peter, I'll try and re-submit the answer paper to the web site. It was set "FOR" Australian Railways Group, but by whom I'm not sure. Cheers, Phill if these are examples of "serious"exam questions no wonder Australia is going backwards! >>> Could someone tell me the correct answer to this test question please. >>> Sorry about the poor picture quality. [quoted text clipped - 20 lines] > Cheers, > Phill Sorry gents, but my ISP bit the dust for a couple of days. To the person who mentioned the offset hinges, that was something I noticed a few days back also. If you wanted maximum strength the diagonal should be welded to the upright at the point where the hinge is mounted. (Pedantic :-) To the person who mentioned cogs v's pulleys, :-) :-) Spot on!! I am still amazed at the variety of answers and explanations, but I am still going to hang my farm gates as in C because I would rather have the grandkids straightening out the diagonal rather than bending it. Thanks to all who participated in this discussion, it's been a hoot :-) I have re scanned the answer sheet and will post the link with the heading ANSWER SHEET. Cheers everyone. Phill. > I have re scanned the answer sheet and will post the link with the > heading ANSWER SHEET. > > Cheers everyone. > > Phill. ## answer sheet is here## http://www.mediafire.com/imageview.php?quickkey=bnoumsmj1td&thumb=4 > > I have re scanned the answer sheet and will post the link with the > > heading ANSWER SHEET. [quoted text clipped - 6 lines] > > http://www.mediafire.com/imageview.php?quickkey=bnoumsmj1td&thumb=4 A (7.36 MB) jpg ...!!!!!!!! all the best.mark >>> I have re scanned the answer sheet and will post the link with the >>> heading ANSWER SHEET. [quoted text clipped - 7 lines] > > all the best.mark Well everyone said they couldn't read it before :-) >>>> I have re scanned the answer sheet and will post the link with the >>>> heading ANSWER SHEET. [quoted text clipped - 9 lines] > >Well everyone said they couldn't read it before :-) No, they couldn't and still can't read your question sheet, maybe because your isp's bandwidth got blown out of the water with the odd few dozen downloads of your seriously overbloated files. As far as your answer file is concerned, a 7.36MB scan of a black and white text page at 1200 ppi with 24 bit colour depth of something that could be conveyed either as a raw text file of less than 1k or as a 50k jpg, gif or tif file shows that far from trying to get answers from all the experts in here you really should learn how to use a scanner properly. -- > No, they couldn't and still can't read your question sheet, maybe > because your isp's bandwidth got blown out of the water with the odd [quoted text clipped - 6 lines] > from all the experts in here you really should learn how to use a > scanner properly. Thanks for the encouragement and constructive criticism Old Duffer. That's a nice warm welcome for a newbie to a newsgroup. I am in fact trying to learn how to use the new scanner, and a new totally foreign (to me) Operating System at the same time. I have re-submitted the Answer sheet as an 84K jpg. My apology for its inflated file size, (Your recommendation was 50K) but that is the lowest resolution available on the new scanner. I may be because I scanned it in Grey Scale, but as a Black & White scan, there was almost no image at all, even in higher resolution. Good luck with trying to read it, despite it's huge size. I have no doubt that I will master it one day, given the benefit of your charm and experience. :-) Cheers, Phill. >> No, they couldn't and still can't read your question sheet, maybe >> because your isp's bandwidth got blown out of the water with the odd [quoted text clipped - 21 lines] > I have no doubt that I will master it one day, given the benefit of your > charm and experience. :-) Doesn't matter what the scanner does. You can adjust and recompress the picture in any photo manipulation software. Paint Shop Pro for example. I can't actually imagine any scanner coming without something similar bundled with it. Mine certainly did. I have to say my sentiments basically agree with the poster above though. I took one look at the 7mb filesize and thought bugger downloading that for ages to see a sheet of text which ought to be a few tens of k in size. SignatureDave Baker - Puma Race Engines >> No, they couldn't and still can't read your question sheet, maybe >> because your isp's bandwidth got blown out of the water with the [quoted text clipped - 24 lines] > Cheers, > Phill. Try using the ocr software that you got with your scanner, edit it and save to a file sending it to newsgroup or what you will. SignatureNeil reverse ra and delete l Linux user 335851 > Try using the ocr software that you got with your scanner, edit it and > save to a file sending it to newsgroup or what you will. Neil, you just described exactly what I did. It's a Canon scanner, came with MP Navigator, which I used to scan to a file size as close as I could get to Old Duffers recommendation of 50K. Lowest I could get was 84K, which should be better than 50K surely??? Anyway, at 84K I can't read it so I have no idea how it could be readable at 50 K. Cheers, Phill. > > Try using the ocr software that you got with your scanner, edit it and > > save to a file sending it to newsgroup or what you will. [quoted text clipped - 8 lines] > Cheers, > Phill. forget the advice in scanning in black and white Ive had terrible results with that . despite it being black and white take my word it will scan better in colour scan colour 300 dpi then edit the pics in adobe photoshop press help in adobe .. drop down menu appears chose resize image f reduce pic in to 650 pixels wide then save ... it will then give you a slider ...you can then reduce it down to about 90k this file then should be pristine and viewable to all . all the best.mark >> Try using the ocr software that you got with your scanner, edit it >> and save to a file sending it to newsgroup or what you will. [quoted text clipped - 8 lines] > Cheers, > Phill. That does sound a rather high file size - I (although I use rarely now) think that about 8k for an A4 size page should be all that is needed after editing and saving. SignatureNeil reverse ra and delete l Linux user 335851 > That does sound a rather high file size - I (although I use rarely > now) think that about 8k for an A4 size page should be all that is > needed after editing and saving. I have tried what Mark suggested and it seems to work better than geyscale to a lower DPI does.....not sure why but thanks Mark. Can't get anything readable at 8K though Neil....I'll keep experimenting Cheers, Phill. |
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