Mechanical aptitude test.

It has already been mentioned that one of the questions says a "force of xx PSI" which is actually a pressure, not a force (edit) Question 41.

Question 15 on lifting the weight assumes frictionless pulleys. If you take friction into account you don't get their answer. I have yet to encounter a frictionless pulley system.
(end edit)

Diesel has a lower auto ignition temperature than petrol does, the reason that petrol autoignites in internal combustion engine is due to it being run near stoichiometric ratios, where as diesel is run very lean. On equivalent mixtures the diesel ignites more readily. From the "Ignition Handbook, V Brabauskas 1992" Diesel AIT 225-256 C, Gasoline 412 C (87 octane), 390 C (92 Octane). Petrol is more volatile , yes. That does not mean it ignites more readily.

My error on the fans.

PS The "Pyro" is not simply a hobby.
 
94% and I would have got two more right (sun and planets and governor) if I had read the questions carefully.

And I would have got 100% if Suction was the right answer - that was a very dodgy question - it's the piston that creates the opportunity for air pressure to work. Air pressure will not move a stationary piston (afaik)

And I agree that the flammability question was poor - especially if it is aimed at students who are expected to learn the difference between spark-ignition and compression ignition-engines.
 
None of the points you make are excuses for getting the questions wrong. I agree the terminology could be better and it should say "a force is applied by the application of a pressure of" rather than "a force is applied" but is that an excuse for getting the question wrong? No! As far as the ignition of gasoline is concerned, everyone knows that it gives off volatile fumes that make it easier to ignite (catch fire) and this is obviously the sense in which the question is phrased. Obviously there are technically friction losses in pulleys but the question is very simple and only gives you a series of selections to answer from so they are obviously talking what used to be 3rd year secondary school mechanics not rocket science.
As you press the point I don't think as a chartered mechanical engineer I would be very happy getting any less than 100% on a schoolboy quiz like this and don't consider it "luck" but if I got anything wrong (and I nearly did by misinterpreting the simple pipework question as a pressure venturi as others did which it isnt because the pressure is relieved by the larger pipe before the reduction in area) I would be upset with myself, not protest loudly to the forum that the questions were wrong. If the questions were about Euclid or Chaucer I would probably get a totally rotten score and wouldn't care and certainly wouldn't say a classics graduate getting them right was "luck" So there! Rant over /forums/images/graemlins/mad.gif /forums/images/graemlins/mad.gif /forums/images/graemlins/mad.gif
 
Parallel lines and the Wife of Bath

Euclid? Geometry? Chaucer? Early English? What advantage would a classics graduate have over an engineer? Next time you're in a university nip round to the Classics dept and ask them what their field covers. Pyro's point is that the questions are badly formed. Seems fair enough to me. I did radio exams over the last couple of years and was amazed at the examiners' weakness in question setting.
 
As far as I could work out by going through it a bit more carefully second time round, the only questions I got "wrong" were the first pulley question and the fans one. There must have been something else, but second time round it didn't show up. My error on the fans, I simply didn't bother thinking about it in enough detail.

As far as chartered engineers go, whoopee and join the club. If I was examining an engineer for Chartered, Master or Phd status I would expect them to account for friction.

Neither the psi question or the gasoline question gave me a problem with selecting the "right" answer, it just showed the lack of detailed knowledge in the person who framed the questions. *shrug*

Have a nice day. /forums/images/graemlins/smile.gif
 
90%
7 x
17 x Don't know why I got that wrong
38 x Looked at the fans from a CW / CCW perspective looking at the front of the fan :-(
44 x water distance up the tube was a surprise
48 x I think that one is Bolox, a piston will suck as it goes down!
 
Suction? Air pressure? Isn't all suction a matter of reducing air pressure and thereby creating a 'sucking' effect? When the piston moves down it 'sucks' the air in - exactly the same thing as saying the higher air pressure outside is pushing it. Both are right. Unless you're a pedantic physicist and say there's no such thing as sucking.

Q.38 the fans: If one is blowing air by turning, let us say, clockwise when face on, the other will be turning counter-clockwise face on. Depends on what you mean by the 'same direction'.

The air pressure question is overly rigorous, while the fans uses a more everyday type of understanding.

Getting 100% implies either having the same mind-set as the examiner or a lot of luck. As to kids getting 100% - how would they know the diff between an overdrive, reverse, direct or reduction gear without Googling it?

I see it's a .com site. I wonder if Americans do better?

Severe sour grapes here. /forums/images/graemlins/mad.gif
 
[ QUOTE ]
I see it's a .com site. I wonder if Americans do better?

[/ QUOTE ]

I came across the test on the honestjohn.co.uk website forum. Some interesting scores and and comments there, although I must say the scores seem lower from motorists......... /forums/images/graemlins/shocked.gif


Here's a link to the HJ forum page about it..... HonestJohn
 
92% but I don't know which ones I got wrong! Agree some were ambiguous - especially the fan one - depending on which way one was looking at the asembly!
 
I had 92% as well. Largely due to A level physics a long time ago, than any aptitude. Also didn't know which ones I had wrong until it was pointed out you can see scores as you go if you click on icon on bottom left earlier in thread. Then went back and gave same answers I did originally, and could see which ones were wrong, though like others, I'd dispute I actually got some of them wrong.
 
Did it again, having discovered how to display the results. Got 96 this time (94 first time)

Still getting the fan question and the gear type question wrong! I am convinced that the "other fan" will rotate in the opposite direction to what it would do if plugged in, perhaps that not what the question meant. Still confused by the gears question.
 
That's exactly what the other fan would do, but the quiz's answer is they go in the same direction - well, it looks the same if they're facing each other and you've got a 4 years old's POV...
 
Did it again. 96% I've no idea what those drive types are. Nothing intuitive about the naming at all. Also flunked on a pulley question.

The shame. The shame.

And I only came in here today to find out about some drill bits... /forums/images/graemlins/frown.gif
 
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