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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#81
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Brain cells needed - 1955 test
On 26/05/2017 21:27, Bill Wright wrote:
On 26/05/2017 14:00, The Natural Philosopher wrote: No, Bill. the joints are tenoned and pinned . They cant pull out. This is utterly basic. A properly made gate or door doesn't need to stress the joints (which are much weaker than the timber members) because the brace pushes up against the cross members. And translates any tendency to sag into a tension force on the top ledge. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#82
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Brain cells needed - 1955 test
"Roger Hayter" wrote in message ... Rod Speed wrote: "Robin" wrote in message ... On 26/05/2017 12:35, Clive George wrote: On 26/05/2017 08:55, Robin wrote: There were more than one question however where there seemed to be insufficient information. The car skid for example. Also the capstan. The one with the weight hanging off rope at the top of the well? There's enough information there. I had in mind the nautical capstan with 4 men and "Which man would have to work hardest to turn the capstan alone?" ISTM "hardest" is ambiguous between (a) the force exerted (highest for shortest lever), Yes, that's the obvious answer. (b) the energy required per unit time (ditto if they walk at the same speed - linear not angular - when walking alone), That's not working harder. and (c) the energy required per revolution (same for all). If you assume the capstan has to be pushed with a constant rotational speed They arent normally, so that cant be assumed and that would have been stated if it was a requirement. then c) is right. If the man has a constant force available he is doing more work the faster he walks so the furthest out one is the answer. But unless the capstan has to be pushed at a constant speed it is a bit hard to see any sensible answer for work done. a) is the obvious answer, because with the longer arm, you have more leverage and so dont have to work so hard. Thats the whole point of the arms. |
#83
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Brain cells needed - 1955 test
On 27/05/17 00:30, John Rumm wrote:
If it were steel, then it would be better in tension - steel is stronger that way, and not going to buckle. Depends on whether its an open frame rather than skinned and on how thick te steel is. Of course steel buckles all the time. The failure mode of most trusses is in fact buckling. -- But what a weak barrier is truth when it stands in the way of an hypothesis! Mary Wollstonecraft |
#84
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Brain cells needed - 1955 test
On 27/05/2017 05:40, The Natural Philosopher wrote:
On 27/05/17 00:30, John Rumm wrote: If it were steel, then it would be better in tension - steel is stronger that way, and not going to buckle. Depends on whether its an open frame rather than skinned and on how thick te steel is. I think you are misreading what I typed. Of course steel buckles all the time. The failure mode of most trusses is in fact buckling. Which is why I was saying you can use a much thinner brace if it is in tension. In tension you don't need to worry about it buckling. In compression it could, and so you would need a stiffer brace to start with. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#85
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Brain cells needed - 1955 test
On Fri, 26 May 2017 22:19:58 +1000, FMurtz wrote:
Graham. wrote: On Thu, 25 May 2017 11:16:16 -0700 (PDT), misterroy wrote: found this test lurking in the filing cabinet at work, some of the questions might need a bit more context. https://drive.google.com/file/d/0B_U...2bnN1c0U/view? usp=sharing Would I be disqualified for putting a mark on the line provided, rather than crossing out the letter corresponding to the correct answer as instructed? You do not need to you can see where the mark is rubbed out. Only in about half the cases. I looked at every "Question" with a view to answering each one and noticed that some had been marked incorrectly, others correctly and some, seemingly not at all. Starting with the boxes one (which is hardest to turn over?) my answers are as follows: C G M assuming diameters of tops of the LH ones = widths of the RH square and equilateral triangular cross sectioned tanks Q All equal A O Move to and fro It wasn't clear what this butcher's weight question was about. I can see three possible 'correct' answers to this one, each depending on how you interpret what the real question is. The previous student's rubbed out answer (V) suggests it was interpreted as a requirement to minimise bending stress on the hanging beam. Another interpretation of the problem is to minimise pull out forces on the beam's anchor rods, suggesting Y as the answer. However, mention of the *heaviest* weight strongly suggests both those answers are wrong due to the use of "Trickery" involving common sense and observational skills in the real world. We know that such butchers' meathook rails are amply over-engineered for the butcher's normal every day usage so we can exclude 'structural integrity' issues from our deliberations (plus, any fatigue induced failure here can be remedied without expensive and painful medical procedures being invoked). This just leaves us with the question of, "If I were that butcher, carrying the heaviest lump of meat from the direction implied by that sketch, where would I want to place it to minimise musculoskeletal wear and tear?" The answer, quite obviously, becomes "The nearest to hand, stupid!", in this case, Z. :-) The only fly in the ointment with this last option is WTF didn't the daft butcher slide all the hooks to the right hand end of the bar beforehand? That way, he could have reduced the strain and effort on his musculoskeletal system even further by arranging for hook V to be nearer again, allowing him to slide the 'heaviest weight' to the far end of the bar with even less strain and effort, leaving the remaining hooks close to hand and available for more '(but slightly less) heavy weights'. I may be wrong in interpreting this question as one of 'ergonomics' but **** it all, that's the only way to make any sense of this one. Moving onto the cups question which seems to be a question of which of the four cups encloses a presumed identical volume of liquid with the least amount of surface area, I'm rather drawn to B despite answers C and D looking like they could be equally as good a choice (the 'All equal' option is rather spoilt by A being quite obviously the one destined to cool the fastest). All of them (cogs question) N Fall V (looks closest to the optimal 45 degree angle ignoring air resistance) A H R V C All equal (assuming we ignore friction effects as Galileo was able to) N Fall Rise and then fall H L R W D (as the previous student indicated, assuming a sweeping bend rather than a tight hairpin bend where the right answer could easily be "All equal"). Again, yet another question where I can't decide whether I'm facing a cunningly disguised question concerned with the dangers of making unwarranted assumptions or just very shoddy question setting. Move in a circle N assuming disks with holes punched in them (in which case, WTF is causing M to remain poised in its depicted position?) S X (assuming equal effort on the part of the 'pushers') Wow! Yet another imponderable question (about skiddiest car). Yet again, we are left to make several assumptions from the very poor quality 'evidence of our eyes' but I'll give it a go. I'm led to assume we are looking at a **** poor sketch of a snapshot overhead view of a sharp bend or corner on a race track and further obliged to assume a dry equally grippy road surface with no adverse camber or rubber crum to penalise any of the cars which I'm further obliged to assume all have equally grippy tyres and are all travelling at the same speed in some sort of race event. Having been forced to make all these assumptions just to drill down to what I *think* is the core of the problem, I can only conclude that car C is most likely to skid due to its higher rate of change of velocity needed to negotiate the bend on a tighter radius than the other three cars which results in higher side forces being applied to the tyres from the resultant centripetal force. In real life, there are many reasons why answer C will be most emphatically wrong but, what the hey, this is just a question on a 1950's mechanics exam paper. :-) H One All equal The mechanism will jam (I'm only 99% sure but if I'm wrong then opposite direction unevenly becomes the only viable alternative) I would hope that such shoddy exam question setting as exhibited by JR Morrisby's efforts would be rejected today. However, I believe (rightly or wrongly) that such shoddiness in examination question standards still abounds to this day. -- Johnny B Good |
#86
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Brain cells needed - 1955 test
On Thu, 25 May 2017 23:52:14 +0100, John Rumm wrote:
On 25/05/2017 21:34, The Natural Philosopher wrote: On 25/05/17 21:27, Bill Wright wrote: On 25/05/2017 19:16, misterroy wrote: found this test lurking in the filing cabinet at work, some of the questions might need a bit more context. https://drive.google.com/file/d/0B_U...2bnN1c0U/view? usp=sharing Is the gate question a trick? H has the brace the wrong way round. Bill tesnd to work either way. There were more than one question however where there seemed to be insufficient information. The car skid for example. The butchers hook one as well... depending what you want to achieve - least load on the supports, then in the middle. Least bending of the rail, then right at the end. Or, as I was forced to conclude, a question of ergonomics relating to reduction of fatigue induced stress on that classic and timeless mechanical system, the musculoskeletal system of the butcher himself! :-) Nothing else made any sense due to lack of information in regard of the rail and its supports. One was left to make far too many completely unwarranted assumptions about the non biological content leaving only the biomechanical and mindset assumptions of the butcher himself as the least contentious of all the possible assumptions that could be made from the cunningly disguised content of that question. If you analyse that question very closely and carefully, you'll realise it was actually a cunningly disguised question of an ergonomically driven common sense based solution to a problem faced by the butcher rather than anything to do with what was least stressful to the hook rail and its supports. Even so, it did beg the question as to why the butcher wasn't clever enough to slide all the hooks to the right hand end of the rail beforehand to ease the load even further but I guess this may have made the required answer all too obvious for the examiner's liking. :-) -- Johnny B Good |
#87
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Brain cells needed - 1955 test
On Fri, 26 May 2017 08:55:15 +0100, Robin wrote:
On 25/05/2017 23:52, John Rumm wrote: On 25/05/2017 21:34, The Natural Philosopher wrote: On 25/05/17 21:27, Bill Wright wrote: On 25/05/2017 19:16, misterroy wrote: found this test lurking in the filing cabinet at work, some of the questions might need a bit more context. https://drive.google.com/file/d/0B_U...2bnN1c0U/view? usp=sharing Is the gate question a trick? H has the brace the wrong way round. No trick. The brace works in both compression and tension and adds the additional stiffness against sag all the other examples were all completely lacking. Bill tends to work either way. There were more than one question however where there seemed to be insufficient information. The car skid for example. Oh yes indeedy! That one needed a ton of (unwarranted in real life) assumptions to be made just to drill down to the core of the question (an issue of which vehicle was being subjected to the highest sideways forces on that part of the corner). Also the capstan. The capstan one was a straight forward "Lever Question". Nothing complicated or tricky about it at all. Again, far too many unknowns to decide whether R would land up working the hardest due to an extremely light load which would make S the more energy efficient option or whether, as was implied, that R would have to work the hardest by virtue of greater effort to move a heavier load. To attempt to answer on the basis of effective energy input by one person alone at each indicated position in turn requires addressing the issue of 'matching impedances' between the generator and the load. Whilst it's true that the energy input by R trotting around the capstan at half the effort is the same as T walking at half the speed but full effort, the energy expended by R and T is unlikely to be the same. If this question is merely a trick question where the correct answer is deemed to be "All equal", then it falls far short of the quality of 'trick question' demonstrated by the Butcher's hook question. The butchers hook one as well... depending what you want to achieve - least load on the supports, then in the middle. Least bending of the rail, then right at the end. Least distance to carry the bloody thing Is the *right* answer! :-) (a cleverly disguised question of ergonomics and perhaps a reminder that the human skeleton and musculature is constrained by the same laws of 'mechanics' as apply to 'engineered' mechanical systems. -- Johnny B Good |
#88
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Brain cells needed - 1955 test
On 27/05/2017 00:28, John Rumm wrote:
On 26/05/2017 21:24, Bill Wright wrote: On 26/05/2017 18:06, John Rumm wrote: [1] e.g. like this one I made earlier: http://wiki.diyfaq.org.uk/index.php/...and_brace_door In which the braces are the correct way! Indeed. On that type of construction, it is the "right" way. For the type pictured in the mechanics paper, it does not matter. What's the difference? Bill |
#89
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Brain cells needed - 1955 test
On 26/05/2017 21:31, Rod Speed wrote:
"Bill Wright" wrote in message news On 26/05/2017 13:59, The Natural Philosopher wrote: No the force has to be compression on the brace. Bill No Bill, It does not Contradiction is not an argument. But it is a statement of fact in this case. It's actually a statement of ********. Bill |
#90
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Brain cells needed - 1955 test
Johnny B Good wrote
FMurtz wrote Graham. wrote misterroy wrote found this test lurking in the filing cabinet at work, some of the questions might need a bit more context. https://drive.google.com/file/d/0B_U...ew?usp=sharing Would I be disqualified for putting a mark on the line provided, rather than crossing out the letter corresponding to the correct answer as instructed? You do not need to you can see where the mark is rubbed out. Only in about half the cases. I looked at every "Question" with a view to answering each one and noticed that some had been marked incorrectly, others correctly and some, seemingly not at all. Yeah, its obviously someone's attempt at the test that has been erased. Starting with the boxes one (which is hardest to turn over?) my answers are as follows: C G M assuming diameters of tops of the LH ones = widths of the RH square and equilateral triangular cross sectioned tanks Yes, that is clearly the intention, your qualifications. Q All equal A O Nope, H Move to and fro It wasn't clear what this butcher's weight question was about. I can see three possible 'correct' answers to this one, each depending on how you interpret what the real question is. Yep, this is by far the poorest question. The previous student's rubbed out answer (V) suggests it was interpreted as a requirement to minimise bending stress on the hanging beam. IMO it is the correct answer, because the two anchors have to be designed to support as heavy a weight as that on all the hooks at once when the track is fully loaded. But then it also wouldnt matter if it was placed on Y for the same reason. Another interpretation of the problem is to minimise pull out forces on the beam's anchor rods, suggesting Y as the answer. However, mention of the *heaviest* weight strongly suggests both those answers are wrong due to the use of "Trickery" involving common sense and observational skills in the real world. Mad. We know that such butchers' meathook rails are amply over-engineered for the butcher's normal every day usage so we can exclude 'structural integrity' issues from our deliberations (plus, any fatigue induced failure here can be remedied without expensive and painful medical procedures being invoked). This just leaves us with the question of, "If I were that butcher, carrying the heaviest lump of meat from the direction implied by that sketch, where would I want to place it to minimise musculoskeletal wear and tear?" The answer, quite obviously, becomes "The nearest to hand, stupid!", in this case, Z. :-) Yours is silly because it would have to have been carried from outside the shop to get to the rail, a much greater distance. The only fly in the ointment with this last option is WTF didn't the daft butcher slide all the hooks to the right hand end of the bar beforehand? Because they dont slide that well with the heaviest weight on them when done as crudely as in the sketch. That way, he could have reduced the strain and effort on his musculoskeletal system even further by arranging for hook V to be nearer again, allowing him to slide the 'heaviest weight' to the far end of the bar with even less strain and effort, leaving the remaining hooks close to hand and available for more '(but slightly less) heavy weights'. You're over wanking this one. I may be wrong in interpreting this question as one of 'ergonomics' but **** it all, that's the only way to make any sense of this one. It doesnt actually make any real sense. Moving onto the cups question which seems to be a question of which of the four cups encloses a presumed identical volume of liquid with the least amount of surface area, I'm rather drawn to B despite answers C and D looking like they could be equally as good a choice (the 'All equal' option is rather spoilt by A being quite obviously the one destined to cool the fastest). I assume C has curved sides to distract those who dont really understand that its the surface area that matters. All of them (cogs question) N Fall V (looks closest to the optimal 45 degree angle ignoring air resistance) A H R V C All equal (assuming we ignore friction effects as Galileo was able to) N Fall Rise and then fall H L R W D (as the previous student indicated, Nope, A because they are all lined up so A has moved the furthest. assuming a sweeping bend rather than a tight hairpin bend where the right answer could easily be "All equal"). Again, yet another question where I can't decide whether I'm facing a cunningly disguised question concerned with the dangers of making unwarranted assumptions or just very shoddy question setting. Nope, you've missed the important fact with this one. Move in a circle N assuming disks with holes punched in them (in which case, WTF is causing M to remain poised in its depicted position?) There will always be some friction. S X (assuming equal effort on the part of the 'pushers') Nope S because he has the smallest leaver. By definition the capstan rotates at a specific speed so my earlier comment about WHY S is correct was wrong, it has nothing to do with the formal definition of what work is, its all about the force required. Wow! Yet another imponderable question (about skiddiest car). Yet again, we are left to make several assumptions from the very poor quality 'evidence of our eyes' but I'll give it a go. I'm led to assume we are looking at a **** poor sketch of a snapshot overhead view of a sharp bend or corner on a race track and further obliged to assume a dry equally grippy road surface with no adverse camber or rubber crum to penalise any of the cars which I'm further obliged to assume all have equally grippy tyres and are all travelling at the same speed in some sort of race event. Yes, if they were different, it would have said that. Having been forced to make all these assumptions just to drill down to what I *think* is the core of the problem, I can only conclude that car C is most likely to skid due to its higher rate of change of velocity needed to negotiate the bend on a tighter radius than the other three cars which results in higher side forces being applied to the tyres from the resultant centripetal force. Yes. In real life, there are many reasons why answer C will be most emphatically wrong Nope. but, what the hey, this is just a question on a 1950's mechanics exam paper. :-) H One All equal The mechanism will jam (I'm only 99% sure but if I'm wrong You are. then opposite direction unevenly becomes the only viable alternative) Nope, opposite direction evenly. This one really sorts out those who have any real mechanical ability. I would hope that such shoddy exam question setting as exhibited by JR Morrisby's efforts would be rejected today. Not a chance. However, I believe (rightly or wrongly) that such shoddiness in examination question standards still abounds to this day. Corse it does. |
#91
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Brain cells needed - 1955 test
"Bill Wright" wrote in message news On 27/05/2017 00:28, John Rumm wrote: On 26/05/2017 21:24, Bill Wright wrote: On 26/05/2017 18:06, John Rumm wrote: [1] e.g. like this one I made earlier: http://wiki.diyfaq.org.uk/index.php/...and_brace_door In which the braces are the correct way! Indeed. On that type of construction, it is the "right" way. For the type pictured in the mechanics paper, it does not matter. What's the difference? The paper has pins at the joints. |
#92
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Brain cells needed - 1955 test
"Bill Wright" wrote in message news On 26/05/2017 21:31, Rod Speed wrote: "Bill Wright" wrote in message news On 26/05/2017 13:59, The Natural Philosopher wrote: No the force has to be compression on the brace. Bill No Bill, It does not Contradiction is not an argument. But it is a statement of fact in this case. It's actually a statement of ********. Nope, and he explained why it can use compression or tension. |
#93
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Brain cells needed - 1955 test
On 26/05/2017 22:30, The Natural Philosopher wrote:
Nevertheless Bill, you are suffering from a common complaint,. you think that the little you do know is all there is to know. That's exactly what you do all the time. You're notorious for it. Those of us who have done this for a living and studied it at university know it aint that simple. Oh **** me! 'I've been to Yooni so I know everything, and I certainly know more than those guys in overalls down there on the site!' How many times have I encountered this blinkered, arrogant attitude? Architects who won't listen to the tradesmen being a good example. Fact is, a guy who's spent his life making things from wood knows a damn sight more about how to make a gate that than someone who thinks they know everything because they're been to Yooni. I discussed this issue with two people. One was a bloke who worked all his life in joinery, first building wooden wagons and later in a workshop turning out various wooden products. The other was a woman who runs a very successful business building furniture and fitting out up- market new houses with doors etc. Both thought the idea of making a gate or door with the brace the wrong was round was such an elementary mistake they wondered if I was joking. So don't give me your high and mighty Yooni ********. I've been putting up with that ****e all my working life and it won't wash. Bill |
#94
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Brain cells needed - 1955 test
On 28/05/17 05:12, Bill Wright wrote:
On 26/05/2017 22:30, The Natural Philosopher wrote: Nevertheless Bill, you are suffering from a common complaint,. you think that the little you do know is all there is to know. That's exactly what you do all the time. You're notorious for it. Those of us who have done this for a living and studied it at university know it aint that simple. Oh **** me! 'I've been to Yooni so I know everything, and I certainly know more than those guys in overalls down there on the site!' How many times have I encountered this blinkered, arrogant attitude? Architects who won't listen to the tradesmen being a good example. Fact is, a guy who's spent his life making things from wood knows a damn sight more about how to make a gate that than someone who thinks they know everything because they're been to Yooni. I discussed this issue with two people. One was a bloke who worked all his life in joinery, first building wooden wagons and later in a workshop turning out various wooden products. The other was a woman who runs a very successful business building furniture and fitting out up- market new houses with doors etc. Both thought the idea of making a gate or door with the brace the wrong was round was such an elementary mistake they wondered if I was joking. So don't give me your high and mighty Yooni ********. I've been putting up with that ****e all my working life and it won't wash. Bill yu remind me of the plumber who came to connect up my UNVENTED hot water tank "In the loft: great place to put it mate, it will increase your water pressure for the showers" He, too, did plumbing for a living. You cling to your beliefs and myths in the face of the simple evidence that no cantilevered structure can exist without at least one joint in tension. you insistence that it mustn't be the diagonal joint is simply arbitrary and bizarre -- Some people like to travel by train because it combines the slowness of a car with the cramped public exposure of an airplane. Dennis Miller |
#95
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Brain cells needed - 1955 test
Johnny B Good wrote:
On Thu, 25 May 2017 23:52:14 +0100, John Rumm wrote: On 25/05/2017 21:34, The Natural Philosopher wrote: On 25/05/17 21:27, Bill Wright wrote: On 25/05/2017 19:16, misterroy wrote: found this test lurking in the filing cabinet at work, some of the questions might need a bit more context. https://drive.google.com/file/d/0B_U...2bnN1c0U/view? usp=sharing Is the gate question a trick? H has the brace the wrong way round. Bill tesnd to work either way. There were more than one question however where there seemed to be insufficient information. The car skid for example. The butchers hook one as well... depending what you want to achieve - least load on the supports, then in the middle. Least bending of the rail, then right at the end. Or, as I was forced to conclude, a question of ergonomics relating to reduction of fatigue induced stress on that classic and timeless mechanical system, the musculoskeletal system of the butcher himself! :-) Alternatively, the answer could be "none of the above" as the meat clearly already has a hook attached and he can hang it on the rail anywhere he likes. Tim -- Please don't feed the trolls |
#96
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Brain cells needed - 1955 test
On 28/05/2017 03:38, Johnny B Good wrote:
The only fly in the ointment with this last option is WTF didn't the daft butcher slide all the hooks to the right hand end of the bar beforehand? That way, he could have reduced the strain and effort on his musculoskeletal system even further by arranging for hook V to be nearer again, allowing him to slide the 'heaviest weight' to the far end of the bar with even less strain and effort, leaving the remaining hooks close to hand and available for more '(but slightly less) heavy weights'. He doesn't need to he has a hook in the meat already and would just hook it on the rail nearest him. I may be wrong in interpreting this question as one of 'ergonomics' but **** it all, that's the only way to make any sense of this one. Moving onto the cups question which seems to be a question of which of the four cups encloses a presumed identical volume of liquid with the least amount of surface area, I'm rather drawn to B despite answers C and D looking like they could be equally as good a choice (the 'All equal' option is rather spoilt by A being quite obviously the one destined to cool the fastest). All of them (cogs question) N Fall V (looks closest to the optimal 45 degree angle ignoring air resistance) A H R V C All equal (assuming we ignore friction effects as Galileo was able to) N Fall truss answer missing here. If the truss has been dimensioned correctly they will all have the same strain but they may well have different loads causing that strain. Rise and then fall doesn't that depend on the taps being identical? if the flow rate is slow the fall will be impossible to see even if you know it is there. H L R W D (as the previous student indicated, assuming a sweeping bend rather than a tight hairpin bend where the right answer could easily be "All equal"). Again, yet another question where I can't decide whether I'm facing a cunningly disguised question concerned with the dangers of making unwarranted assumptions or just very shoddy question setting. Its the inside one assuming they depict someone going around the same bend as you have to lean more the faster you go around the bends which is why motorcylists scrape their knees and then fall off. Move in a circle N assuming disks with holes punched in them (in which case, WTF is causing M to remain poised in its depicted position?) The examiners hand. S It depends how you define work. S would have to push hardest but travel less distance. In reality he wouldn't be able to shift the thing as you wouldn't have four operating positions if you only needed one man to do the job. X (assuming equal effort on the part of the 'pushers') Wow! Yet another imponderable question (about skiddiest car). Yet again, we are left to make several assumptions from the very poor quality 'evidence of our eyes' but I'll give it a go. I'm led to assume we are looking at a **** poor sketch of a snapshot overhead view of a sharp bend or corner on a race track and further obliged to assume a dry equally grippy road surface with no adverse camber or rubber crum to penalise any of the cars which I'm further obliged to assume all have equally grippy tyres and are all travelling at the same speed in some sort of race event. Having been forced to make all these assumptions just to drill down to what I *think* is the core of the problem, I can only conclude that car C is most likely to skid due to its higher rate of change of velocity needed to negotiate the bend on a tighter radius than the other three cars which results in higher side forces being applied to the tyres from the resultant centripetal force. In real life, there are many reasons why answer C will be most emphatically wrong but, what the hey, this is just a question on a 1950's mechanics exam paper. :-) Looking at it C can't be turning yet or the rear wheels will hit the curb. B is going to have to turn sharpest or he will hit A. I would say B because he is going to have to hit the brakes to avoid A. H One All equal The mechanism will jam (I'm only 99% sure but if I'm wrong then opposite direction unevenly becomes the only viable alternative) doesn't the sliding pivot stop it from jamming? I would hope that such shoddy exam question setting as exhibited by JR Morrisby's efforts would be rejected today. However, I believe (rightly or wrongly) that such shoddiness in examination question standards still abounds to this day. Well done. have a gold star. |
#97
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Brain cells needed - 1955 test
On Sun, 28 May 2017 11:07:10 +0100, dennis@home wrote:
On 28/05/2017 03:38, Johnny B Good wrote: The only fly in the ointment with this last option is WTF didn't the daft butcher slide all the hooks to the right hand end of the bar beforehand? That way, he could have reduced the strain and effort on his musculoskeletal system even further by arranging for hook V to be nearer again, allowing him to slide the 'heaviest weight' to the far end of the bar with even less strain and effort, leaving the remaining hooks close to hand and available for more '(but slightly less) heavy weights'. He doesn't need to he has a hook in the meat already and would just hook it on the rail nearest him. Nicely spotted! :-) If this was a question of observational skills and 'common sense' (as it seems since it's the only way to make any sense of it), then I'm afraid I've only got half marks (and the question setter zero marks for failing to provide any means for the student to demonstrate the 'best answer'). I may be wrong in interpreting this question as one of 'ergonomics' but **** it all, that's the only way to make any sense of this one. Moving onto the cups question which seems to be a question of which of the four cups encloses a presumed identical volume of liquid with the least amount of surface area, I'm rather drawn to B despite answers C and D looking like they could be equally as good a choice (the 'All equal' option is rather spoilt by A being quite obviously the one destined to cool the fastest). All of them (cogs question) N Fall V (looks closest to the optimal 45 degree angle ignoring air resistance) A H R V C All equal (assuming we ignore friction effects as Galileo was able to) N Fall truss answer missing here. Oops! 'My Bad'. :-( I'm afraid I was so hung up on trying to work out an answer to this one, I decided to 'deal with it later' and moved onto the rest of the questions, forgetting to return to it before posting my follow up. If the truss has been dimensioned correctly they will all have the same strain but they may well have different loads causing that strain. I got as far as seeing this as a "vectors" calculation, depending on (yet more) assumptions that the strains due to the mass of the bridge components themselves would be insignificant enough compared to the "1 ton load" and largely balance themselves out of the equation for the purpose of this question anyway as well assuming the structure is made up entirely from right angled isosceles triangles. With all those assumptions in place (all pigs prepped up and ready to fly, so to speak), I can see that members V and X are in tension to the tune of 0.707 tons with W and Y each carrying a 1 ton force in compression. It is impossible to correctly answer this question when complying with the instruction to select "The one and only correct option" from the list supplied since I'd want to select the *two* correct options, V and X. If I ignore my understanding of the examiner's definition of the word 'strain' to decide the most likely singularly correct option, I'd be forced by such logic to select 'All equal' and hope I'd correctly 'second guessed' the examiner's definition of a 'correct answer'. OTOH, it may simply show my ignorance of the mechanics of bridge construction and the definition of 'strain'. :-) Rise and then fall doesn't that depend on the taps being identical? No, it depends on the taps *not* being identical; in this case the LHS tap of tank X being a much larger bore, matching the fatter pipework allowing a faster fill rate than the smaller tap and pipework linking to the tank on the RHS of tank X will allow it to drain away. Rise and then fall describes exactly what will happen to the water level in tank X during the early part of the process. Eventually, the water levels in all three tanks will level off. The level in the LHS tank will only fall whilst that in the RHS tank will only rise. Tank X is the only one of the three that will exhibit this 'interesting behaviour' in the scenario depicted. if the flow rate is slow the fall will be impossible to see even if you know it is there. The question is about what happens to the water level in tank X regardless of whether or not it can be observed. The sketch shows three, apparently transparent tanks, along with quite obviously different sized 'taps' (valves) and plumbing to save the student from thinking up ways to impose difficulties in arriving at a correct answer. :-) H L R W D (as the previous student indicated, assuming a sweeping bend rather than a tight hairpin bend where the right answer could easily be "All equal"). Again, yet another question where I can't decide whether I'm facing a cunningly disguised question concerned with the dangers of making unwarranted assumptions or just very shoddy question setting. Its the inside one assuming they depict someone going around the same bend as you have to lean more the faster you go around the bends which is why motorcylists scrape their knees and then fall off. No, the ambiguity lies in the fact that the amount of lean to balance centripetal force depends not on the speed alone but that of the velocity change (in this case a change of velocity due to a change in direction rather than speed). This sketch could be a snapshot of a group of riders negotiating a hairpin bend on a wide road where the innermost rider, D, is in fact moving at the slowest speed but requiring the most lean to balance the higher change of velocity due to the much tighter turn being made on the inside of the bend. Indeed, it's just as possible to have this set up so that all riders are travelling at the same scalar speed and show the same succession of increasing lean angles. This yet another badly set question wherein the only way the examiner could have saved himself from total and utter disgrace would be by replacing the "All equal" option with "Totally impossible to discern from the given sketch". Move in a circle N assuming disks with holes punched in them (in which case, WTF is causing M to remain poised in its depicted position?) The examiners hand. That lacked a smiley imho. :-) S It depends how you define work. S would have to push hardest but travel less distance. In reality he wouldn't be able to shift the thing as you wouldn't have four operating positions if you only needed one man to do the job. X (assuming equal effort on the part of the 'pushers') Wow! Yet another imponderable question (about skiddiest car). Yet again, we are left to make several assumptions from the very poor quality 'evidence of our eyes' but I'll give it a go. I'm led to assume we are looking at a **** poor sketch of a snapshot overhead view of a sharp bend or corner on a race track and further obliged to assume a dry equally grippy road surface with no adverse camber or rubber crum to penalise any of the cars which I'm further obliged to assume all have equally grippy tyres and are all travelling at the same speed in some sort of race event. Having been forced to make all these assumptions just to drill down to what I *think* is the core of the problem, I can only conclude that car C is most likely to skid due to its higher rate of change of velocity needed to negotiate the bend on a tighter radius than the other three cars which results in higher side forces being applied to the tyres from the resultant centripetal force. In real life, there are many reasons why answer C will be most emphatically wrong but, what the hey, this is just a question on a 1950's mechanics exam paper. :-) Looking at it C can't be turning yet or the rear wheels will hit the curb. B is going to have to turn sharpest or he will hit A. I would say B because he is going to have to hit the brakes to avoid A. H One All equal The mechanism will jam (I'm only 99% sure but if I'm wrong then opposite direction unevenly becomes the only viable alternative) doesn't the sliding pivot stop it from jamming? I think the sliding pivot is most likely the reason it *will* jam up imo (varying ratio of the linking bar as a lever). Now that I've had a break from pondering this question, it seems to me to be a question of can such a linkage without the extreme and unusual wear on the centre pin bearing of the linkage bar even work? Consider this; shrink the slot in the linkage bar down to a round hole for the pivot pin bearing and you'll see straight away that such a linkage cannot allow movement (you land up with two triangles which cannot be contorted without bending or altering at least one of the connecting lines. You might think turning the bearing hole in the middle of the linkage bar into an elongated slot will help but the problem there is that the varying lever ratios will still result in a jammed machine. I may not have been entirely sure of my initial answer last night but, having taken another look at the problem in the bright light of day, I'm now convinced that the mechanism *will* jam. :-) I would hope that such shoddy exam question setting as exhibited by JR Morrisby's efforts would be rejected today. However, I believe (rightly or wrongly) that such shoddiness in examination question standards still abounds to this day. Well done. have a gold star. Thank you very much! You're so kind. :-) -- Johnny B Good |
#98
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Brain cells needed - 1955 test
On Sun, 28 May 2017 06:38:57 +0000, Tim+ wrote:
Johnny B Good wrote: On Thu, 25 May 2017 23:52:14 +0100, John Rumm wrote: On 25/05/2017 21:34, The Natural Philosopher wrote: On 25/05/17 21:27, Bill Wright wrote: On 25/05/2017 19:16, misterroy wrote: found this test lurking in the filing cabinet at work, some of the questions might need a bit more context. https://drive.google.com/file/d/0B_U...2bnN1c0U/view? usp=sharing Is the gate question a trick? H has the brace the wrong way round. Bill tesnd to work either way. There were more than one question however where there seemed to be insufficient information. The car skid for example. The butchers hook one as well... depending what you want to achieve - least load on the supports, then in the middle. Least bending of the rail, then right at the end. Or, as I was forced to conclude, a question of ergonomics relating to reduction of fatigue induced stress on that classic and timeless mechanical system, the musculoskeletal system of the butcher himself! :-) Alternatively, the answer could be "none of the above" as the meat clearly already has a hook attached and he can hang it on the rail anywhere he likes. An excellent point! Sadly, the rules of the game, as set by the examiner, rather precludes such an accurate answer. Indeed, this has meant that quite a few of the other questions have also been blighted by this same limitation. :-( -- Johnny B Good |
#99
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Brain cells needed - 1955 test
Johnny B Good wrote:
On Sun, 28 May 2017 06:38:57 +0000, Tim+ wrote: Or, as I was forced to conclude, a question of ergonomics relating to reduction of fatigue induced stress on that classic and timeless mechanical system, the musculoskeletal system of the butcher himself! :-) Alternatively, the answer could be "none of the above" as the meat clearly already has a hook attached and he can hang it on the rail anywhere he likes. An excellent point! Sadly, the rules of the game, as set by the examiner, rather precludes such an accurate answer. Indeed, this has meant that quite a few of the other questions have also been blighted by this same limitation. :-( And yet another potentially correct answer... "It doesn't matter where he hangs it if the bar and supports have been adequately engineered". If it hasn't been, then it all depends on which bit of the system hasn't been adequately engineered, the bar or the bar supports. Tim -- Please don't feed the trolls |
#100
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Brain cells needed - 1955 test
The Natural Philosopher wrote:
On 28/05/17 05:12, Bill Wright wrote: On 26/05/2017 22:30, The Natural Philosopher wrote: Nevertheless Bill, you are suffering from a common complaint,. you think that the little you do know is all there is to know. That's exactly what you do all the time. You're notorious for it. Those of us who have done this for a living and studied it at university know it aint that simple. Oh **** me! 'I've been to Yooni so I know everything, and I certainly know more than those guys in overalls down there on the site!' How many times have I encountered this blinkered, arrogant attitude? Architects who won't listen to the tradesmen being a good example. Fact is, a guy who's spent his life making things from wood knows a damn sight more about how to make a gate that than someone who thinks they know everything because they're been to Yooni. I discussed this issue with two people. One was a bloke who worked all his life in joinery, first building wooden wagons and later in a workshop turning out various wooden products. The other was a woman who runs a very successful business building furniture and fitting out up- market new houses with doors etc. Both thought the idea of making a gate or door with the brace the wrong was round was such an elementary mistake they wondered if I was joking. So don't give me your high and mighty Yooni ********. I've been putting up with that ****e all my working life and it won't wash. Bill yu remind me of the plumber who came to connect up my UNVENTED hot water tank "In the loft: great place to put it mate, it will increase your water pressure for the showers" He, too, did plumbing for a living. You cling to your beliefs and myths in the face of the simple evidence that no cantilevered structure can exist without at least one joint in tension. you insistence that it mustn't be the diagonal joint is simply arbitrary and bizarre Looking at how a wooden gate is made: 1. Given that you need good joints at all four corners, it is not hard to make the top ones capable of reisting tension with no additional work. A diagonal brace in compression needs hardly any jointing at all as it has vertical and lateral compression forces against its trianguar end and just needs stabilising in place with a very simple joint or metal hardware. So you save two elaborate carpentry joints. 2. If the diagonal strut bears on the uprights as well as the horizontals it should be possible to distribute the tension between all four joints, and all four main members, I am sure there is a reason why gates are made with wooden diagonals in compression, or, as I have seen, steel cable diagonals in tension. -- Roger Hayter |
#101
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Brain cells needed - 1955 test
On 28/05/2017 05:01, Rod Speed wrote:
"Bill Wright" wrote in message news On 27/05/2017 00:28, John Rumm wrote: On 26/05/2017 21:24, Bill Wright wrote: On 26/05/2017 18:06, John Rumm wrote: [1] e.g. like this one I made earlier: http://wiki.diyfaq.org.uk/index.php/...and_brace_door In which the braces are the correct way! Indeed. On that type of construction, it is the "right" way. For the type pictured in the mechanics paper, it does not matter. What's the difference? The paper has pins at the joints. Pins are a weak point. They can shrink and fall out, or rot away. Bill |
#102
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Brain cells needed - 1955 test
On 28/05/2017 07:04, The Natural Philosopher wrote:
yu remind me of the plumber who came to connect up my UNVENTED hot water tank "In the loft: great place to put it mate, it will increase your water pressure for the showers" He, too, did plumbing for a living. So you picked a crap plumber (probably the one who could come quickest because he didn't have much work on) and because he was crap you feel that you can disregard the accumulated wisdom of all tradesmen. Bill |
#103
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Brain cells needed - 1955 test
On 28/05/2017 19:34, Roger Hayter wrote:
The Natural Philosopher wrote: On 28/05/17 05:12, Bill Wright wrote: On 26/05/2017 22:30, The Natural Philosopher wrote: Nevertheless Bill, you are suffering from a common complaint,. you think that the little you do know is all there is to know. That's exactly what you do all the time. You're notorious for it. Those of us who have done this for a living and studied it at university know it aint that simple. Oh **** me! 'I've been to Yooni so I know everything, and I certainly know more than those guys in overalls down there on the site!' How many times have I encountered this blinkered, arrogant attitude? Architects who won't listen to the tradesmen being a good example. Fact is, a guy who's spent his life making things from wood knows a damn sight more about how to make a gate that than someone who thinks they know everything because they're been to Yooni. I discussed this issue with two people. One was a bloke who worked all his life in joinery, first building wooden wagons and later in a workshop turning out various wooden products. The other was a woman who runs a very successful business building furniture and fitting out up- market new houses with doors etc. Both thought the idea of making a gate or door with the brace the wrong was round was such an elementary mistake they wondered if I was joking. So don't give me your high and mighty Yooni ********. I've been putting up with that ****e all my working life and it won't wash. Bill yu remind me of the plumber who came to connect up my UNVENTED hot water tank "In the loft: great place to put it mate, it will increase your water pressure for the showers" He, too, did plumbing for a living. You cling to your beliefs and myths in the face of the simple evidence that no cantilevered structure can exist without at least one joint in tension. you insistence that it mustn't be the diagonal joint is simply arbitrary and bizarre Looking at how a wooden gate is made: 1. Given that you need good joints at all four corners, it is not hard to make the top ones capable of reisting tension with no additional work. A diagonal brace in compression needs hardly any jointing at all as it has vertical and lateral compression forces against its trianguar end and just needs stabilising in place with a very simple joint or metal hardware. So you save two elaborate carpentry joints. 2. If the diagonal strut bears on the uprights as well as the horizontals it should be possible to distribute the tension between all four joints, and all four main members, I am sure there is a reason why gates are made with wooden diagonals in compression It's always been done like that because when people have done it the other way the gate has been less strong. It's even in the Bible. Nathaniel who worked for the Council came to Jesus in the tenth hour when it was his teabreak and he did sayeth unto him, Can you maketh a good gate for the Garden of Gethsemane? It must be a proper gate that will gladden the hearts of all who know anything about woodwork when they see it. Jesus said Whence thou knowest me? Nathaniel answered I know you are a carpenter and also the Son of God on Sundays so you aught to do a good job. Jesus drank of his tea and said, You had a gate for the Garden, when I passed by there seven days ago, for I saw it with mine own eyes, though it looked like a poor gate I must say. Nathaniel said, That gate was as worthless as the dung that falls from a dog, and the man who made it was a wastrel and a vagabond. For he put the brace the wrong way round and the gate fell into many pieces, and the pieces still lay on the ground, except for the one that I threw at the wastrel's head. Jesus was pleased at this chance to show his worth and become favoured by the Council for he saw that many lucrative jobs might come unto him by those means, so he did make a gate, and it was sturdy and fully children proof with the brace the way His Father had ordained braces must be. And so the gate was good, and Nathaniel paid Jesus, and gave him a tip. The next day when the soldiers came for Jesus to take him to Calvary where they would kill him he pointed to the man who had made the first gate, and said, Take that man instead of me for he cannot make a good gate but I have made an excellent gate and it's over there if you want to cast thine eyes over it. The soldiers went to Jesus' gate and one said, This gate is good for many reasons but the main one is that the brace is the right way round. So the soldiers took the wastrel who had made the first gate and nailed him to a cross and forgot about Jesus for the time being. But the wastrel was the man who had made the cross on which he suffered, for he had worked for the Council making various things, and he had put the brace above the crossarm instead of below it, so it was in tension instead of compression. The pins were rent asunder for the man was exceedingly stout and the crossarm falleth to the ground, and the man ran away. After these events had passed Jesus became the Main Man with the Council, so it was he who made all the crosses from then on. He made them how his Father (and his dad Joseph) had said they should be made, so they were exceeding strong. So when the soldiers came again and took Jesus and nailed him to a cross, the cross did not break, and Jesus was stuck there, and he cried Oh God why hast thou betrayed me? and God answered, Part of thy skill should be to know when to botch. Think about it my Son. |
#104
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Brain cells needed - 1955 test
"Bill Wright" wrote in message news On 28/05/2017 05:01, Rod Speed wrote: "Bill Wright" wrote in message news On 27/05/2017 00:28, John Rumm wrote: On 26/05/2017 21:24, Bill Wright wrote: On 26/05/2017 18:06, John Rumm wrote: [1] e.g. like this one I made earlier: http://wiki.diyfaq.org.uk/index.php/...and_brace_door In which the braces are the correct way! Indeed. On that type of construction, it is the "right" way. For the type pictured in the mechanics paper, it does not matter. What's the difference? The paper has pins at the joints. Pins are a weak point. They can shrink and fall out, or rot away. Irrelevant to what was in the TEST. |
#105
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Brain cells needed - 1955 test
On Sun, 28 May 2017 17:23:38 +0000, Tim+ wrote:
Johnny B Good wrote: On Sun, 28 May 2017 06:38:57 +0000, Tim+ wrote: Or, as I was forced to conclude, a question of ergonomics relating to reduction of fatigue induced stress on that classic and timeless mechanical system, the musculoskeletal system of the butcher himself! :-) Alternatively, the answer could be "none of the above" as the meat clearly already has a hook attached and he can hang it on the rail anywhere he likes. An excellent point! Sadly, the rules of the game, as set by the examiner, rather precludes such an accurate answer. Indeed, this has meant that quite a few of the other questions have also been blighted by this same limitation. :-( And yet another potentially correct answer... "It doesn't matter where he hangs it if the bar and supports have been adequately engineered". If it hasn't been, then it all depends on which bit of the system hasn't been adequately engineered, the bar or the bar supports. That's exactly the problem, Ambiguity! (and in spades!). In fact there's so many of these ambiguously posed questions sprinkled around where the only way the student can provide the (or most) correct answer is by 'breaking the rules' in regard of indicating which of five possible answers is the correct *one* that it makes me wonder whether this (contrary to most examination papers) was designed specifically to identify budding geniuses (or troublemakers) prepared to stand up and be counted. It's almost as if this was some sort of inverse precursor to "The Milgram Experiment"[1] which was carried out in 1961 at Yale University to examine the issue of "Obedience" which had been raised at the Nazi war criminal trials by the defendants' claims that "They were just following orders." I guess it's the common factor of the deceitful nature of that sprinkling of "Trick Questions" embedded in the exam paper that's made me think of the Milgram Experiment which had relied entirely upon deception to gain insight into the nature of obedience to authority figures. In the case of this exam paper, one would prefer to think of it as a way to identify free thinking geniuses as candidates for further educational advancement but it could just as easily be a way to deal with potential trouble makers by denying them access to further education. How the test results are interpreted depends on the aims of the sponsor who may not necessarily have taken the question setter entirely into his confidence [2]. [1] https://www.simplypsychology.org/milgram.html [2] Perhaps I'm overthinking this. I seem to be in danger of developing a conspiracy theory. My apologies. If there's one thing the world isn't running short of, it's conspiracy theories. :-( -- Johnny B Good |
#106
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Brain cells needed - 1955 test
On 28/05/2017 04:49, Bill Wright wrote:
On 27/05/2017 00:28, John Rumm wrote: On 26/05/2017 21:24, Bill Wright wrote: On 26/05/2017 18:06, John Rumm wrote: [1] e.g. like this one I made earlier: http://wiki.diyfaq.org.uk/index.php/...and_brace_door In which the braces are the correct way! Indeed. On that type of construction, it is the "right" way. For the type pictured in the mechanics paper, it does not matter. What's the difference? In a framed construction, the brace is inline with the other timbers. This means that its not easy to make a joint at the brace ends that would work well in tension unless you are going to opt for more difficult to construct angled M&T joints. So the expedient option is to ensure this brace is oriented that it acts in compression like a gallows bracket, since this puts little stress on the fixing points of the brace. With a picket style construction like that shown in the paper, all the joints are simply planted on top of each other and fixed with a bolt through the faces (rather like you were bolting together three lengths of Meccano). Unlike M&T joinery, there is no inherent ability of the joints themselves to resist racking, everything comes down to shear loads on the bolts caused by the triangulation. Some will be in compression and some in tension. You can argue in the latter case that the brace used in the "wrong" orientation will have a failure mode with the fixing tearing out of the end of the brace (or the bolt shearing - depending on whether the bolt or gate material is stronger). This would be true, but in the circumstance with the "right" orientation, you simply get the same failure at the end of the top cross member instead. The engineering approach will often opt for the tension brace in circumstances like this since it can be much thinner and needs no inherent stiffness. (as someone else mentioned, even a cable would function here). The result being a lighter (so less self loading in the first place) and cheaper to construct gate. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#107
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Brain cells needed - 1955 test
On 28/05/2017 17:19, Johnny B Good wrote:
On Sun, 28 May 2017 06:38:57 +0000, Tim+ wrote: Johnny B Good wrote: On Thu, 25 May 2017 23:52:14 +0100, John Rumm wrote: On 25/05/2017 21:34, The Natural Philosopher wrote: On 25/05/17 21:27, Bill Wright wrote: On 25/05/2017 19:16, misterroy wrote: found this test lurking in the filing cabinet at work, some of the questions might need a bit more context. https://drive.google.com/file/d/0B_U...2bnN1c0U/view? usp=sharing Is the gate question a trick? H has the brace the wrong way round. Bill tesnd to work either way. There were more than one question however where there seemed to be insufficient information. The car skid for example. The butchers hook one as well... depending what you want to achieve - least load on the supports, then in the middle. Least bending of the rail, then right at the end. Or, as I was forced to conclude, a question of ergonomics relating to reduction of fatigue induced stress on that classic and timeless mechanical system, the musculoskeletal system of the butcher himself! :-) Alternatively, the answer could be "none of the above" as the meat clearly already has a hook attached and he can hang it on the rail anywhere he likes. An excellent point! Sadly, the rules of the game, as set by the examiner, rather precludes such an accurate answer. Indeed, this has meant that quite a few of the other questions have also been blighted by this same limitation. :-( I think one has to read the hook in the meat as being the "real" hook, and those depicted on the rail simply being virtual hooks indication possible positions where the real hook may be placed. Kind of like quantum hooks, you have a hook superposition, and its only when you collapse the wave function you get to work out where it is! ;-) -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#108
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Brain cells needed - 1955 test
On Mon, 29 May 2017 10:39:32 +0100, John Rumm wrote:
On 28/05/2017 17:19, Johnny B Good wrote: On Sun, 28 May 2017 06:38:57 +0000, Tim+ wrote: Johnny B Good wrote: On Thu, 25 May 2017 23:52:14 +0100, John Rumm wrote: On 25/05/2017 21:34, The Natural Philosopher wrote: On 25/05/17 21:27, Bill Wright wrote: On 25/05/2017 19:16, misterroy wrote: found this test lurking in the filing cabinet at work, some of the questions might need a bit more context. https://drive.google.com/file/d/0B_U...BuTFU2bnN1c0U/ view? usp=sharing Is the gate question a trick? H has the brace the wrong way round. Bill tesnd to work either way. There were more than one question however where there seemed to be insufficient information. The car skid for example. The butchers hook one as well... depending what you want to achieve - least load on the supports, then in the middle. Least bending of the rail, then right at the end. Or, as I was forced to conclude, a question of ergonomics relating to reduction of fatigue induced stress on that classic and timeless mechanical system, the musculoskeletal system of the butcher himself! :-) Alternatively, the answer could be "none of the above" as the meat clearly already has a hook attached and he can hang it on the rail anywhere he likes. An excellent point! Sadly, the rules of the game, as set by the examiner, rather precludes such an accurate answer. Indeed, this has meant that quite a few of the other questions have also been blighted by this same limitation. :-( I think one has to read the hook in the meat as being the "real" hook, and those depicted on the rail simply being virtual hooks indication possible positions where the real hook may be placed. Kind of like quantum hooks, you have a hook superposition, and its only when you collapse the wave function you get to work out where it is! ;-) Brilliant! Perhaps this examination paper has been designed to spot not only budding geniuses but geniuses with the potential to make budding geniuses look like a bunch of cretins. Genius! :-) -- Johnny B Good |
#109
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Brain cells needed - 1955 test
On 28/05/2017 21:02, Rod Speed wrote:
Pins are a weak point. They can shrink and fall out, or rot away. Irrelevant to what was in the TEST. We've moved on from that. Bill |
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