I got the website, but the test didn't show. There was a little box with a red cross in it, but it didn't respond to either a left or a right click. What am I doing wrong?
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L\'escargot.
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what browser you using? its needs be able to load the adobe flash plug in.
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< Ex RF, Ex TVM >
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46/50 92%
Got 4 wrong
7, 8, 19, 48.
Tho I am sure I was right on 48. Its the vacuum that causes air to enter the piston, is this suction or atmospheric pressure. Conflict of terms perhaps.
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< Ex RF, Ex TVM >
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>>Its the vacuum that causes air to enter the piston
That it's certainly not. It's an area of lower-than-atmospheric pressure.
Which is itself caused by the piston moving down, which causes atmospheric pressure to push air into the cylinder.
Bad question.
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Ok so its not a true vacuum. Its a vacuum effect tho.
The air entering the piston is a consequence of the vacuum effect (or area of lower pressure)
So whats the cause? the cause is the piston going down.
Agree bad question.
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< Ex RF, Ex TVM >
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Odd for a Ford site - didn't notice anything on how you re-programme an injector or where you buy the purest diesel for your TDCI ;-)
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^^^^^^PMSL ^^^^^
I thought something similar but then thought it was a bit of a cheap shot ;-)
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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84% :o)
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Grrrr. I was beaten for the "mechanical numpty" award by teabelly. 68%.
Mind you, 6 or 7 of my wild guesses turned out to be correct!
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Made 82% (ie 41/50)
Faltered on electrical and little bit on hydraulics! On two pulley questions guesstimate appeared to be correct!
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86%, although at least a couple of the questions I answered in haste and realised I had hit the incorrect answer as I submitted it-so my adjusted score is over 90% :-). Couldn't get my head around that worm screw question-don't get me wrong I understand it but couldn't get my brain to see the thread turn direction :-(
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"is this suction or atmospheric pressure"
Fair question, and an unfair distinction in a quiz, IMHO. Suction is the observable effect of allowing atmospheric pressure to do its work when there is an imbalance. Centrifugal force doesn't officially exist either, but everyone knows what it is, and even scientists use centrifuges (and suction pumps)...
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If the piston remains static; then the air stays where it is.
Therefore the only answer is the action of moving the piston causes the air to enter.
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If the piston remains static; then the air stays where it is. Therefore the only answer is the action of moving the piston causes the air to enter.
This is like that "chicken and egg" conversation the rats have at the end of the Chicken Run film ;-)
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90%. Couldn't get the worm drive one right in my head, for no good reason.
Memo to self: connecting batteries in SERIES increases voltage. Duh.
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92%
I felt that the questions were rather badly worded. I would hope that they wouldn't appear like that on a real examination question.
It might be more accurate to say that nature abhors pressure! (being that most of the universe is remarkably close to vacuum conditions)
Number_Cruncher
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82%. No idea which I got wrong.
The long belt and series of pulleys gave me a headache.
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90%.
I got the suck/air pressure one right, it having been drummed into us years ago at school that there was no such thing as suck, like centrifugal force.
But I thought a lot of the questions were badly worded. I pondered over the angled shot of the bevel gears - did it mean direction as we view it, or is there a convention regarding gears on the end of shafts?
Major fault we would have been shot for at school - Kg etc is a MASS not a FORCE. The unit of force would be a Kilogram-weight.
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I plumped for atmospheric pressure; ISTR reading a definition of 'naturally aspirated' in an engineering dictionary which said "air enters due to atmospheric pressure".
I can't find a more highbrow source but good old Wikipedia says the above, but then you click a link and it says vacuum + air pressure + venturi effect of valves. So a bit ambiguous.
en.wikipedia.org/wiki/Aspirated
But I fluffed the quiz on some of the gearing and electrical questions and got 86%, with much twirling of fingers to imagine gears/ fans turning!
;o)
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What does everyone mean 'There's no such thing as suck or centrifugal'?
How is all the air removed from a vacuum vessel (what ever it's called) and how do the motorbikes stay on the wall in the Wall of Death if there's no such thing as centrifugal force?
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Aim low, expect nothing & dont be disappointed
Edited by Sim-O on 24/10/2007 at 14:19
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how do the motorbikes stay on the wall in the Wall of Death if there's no such thing as centrifugal force?
By angling the bike slightly up the wall and driving fast enough to ensure that the 'down' force provided by gravity is matched by the 'up' force from the bike.
It's no different from steering slightly into a crosswind to avoid being blown off the road.
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There is no such thing as centrifugal force.
Imagine a conker. Forget about gravity for a moment, so float it in mid air. Give it a gentle push, and it will want to disappear off in a straight line.
Now dangle the conker on a piece of string. Again, give it a gentle horizontal push, and it will try to disappear off horizontally. Things move in straight lines unless subject to additional forces. BUT, it's attached to a piece of string. So it has to go in a circle. The string is constraining its movement into a circle; therefore the string is exerting a force on the conker. We call it a centripetal force.
Now, whizz the conker round in a circle and cut the string. It will fly off at a tangent to the circle. You have removed the centripetal force that is keeping it on its circular track, so it goes off in a straight line. There is no "centrifugal" force acting on the conker; there is in fact no force at all acting on the conker - that's why it goes in a straight line. So there certainly can't be a centrifugal force.
But you say, I can feel centrifugal force. If I throw a hammer in athletics, I can feel it trying to move away from me. It can dislocate my shoulder! The answer is no. You are in fact applying a centripetal force to the hammer. It is not applying a centrifugal force to you.
Centrifugal force is perhaps sloppy shorthand for "absence of centripetal force".
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Centrifugal Force
an outward force on a body rotating about an axis, assumed equal and opposite to the centripetal force and postulated to account for the phenomena seen by an observer in the rotating body.
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< Ex RF, Ex TVM >
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Ok. That's centrifugal force sorted. I think.
What about 'there's no such thing as suck'?
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Aim low, expect nothing & dont be disappointed
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What about 'there's no such thing as suck'? ----------------------------------------------
An example of what I think is called a "privative" i.e. a noun which is the absence of something. The classic example is DARK which is not a thing in itself merely the absence of light.
cf the works of Terry Pratchett
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'Suck' is a verb.
To suck
End of English class.
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"much twirling of fingers to imagine gears/ fans turning!"
Same here. The fans were particularly tricky, I thought. I took 'turning in the same direction' to mean WRT the fan, but of course they meant WRT the illustration...
(one's blowing, and the other's turning as if to suck*)
*assuming such a thing is possible :-)
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86%
Good fun for a lunchtime.
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scraped through with 80
hangs head in shame and wanders back to work as a motor trade professional
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Ooer .....Horrible memories of physics lessons at school 45 or so years ago.
I did the test very quickly , took a few wild guesses and failed . I got clickety click in bingo parlance so not quite as bad as some.
Should have paid more attention in class - Must try harder.........
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Only 88%, and frankly I am miffed.
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That's very well put, mapmaker, if I may say so.
I think I could have got 100 %, he says modestly, if I had given some of the questions a bit more thought. I started quite seriously, but when I saw I was still only half way through I got deliberately careless and started ticking intuitively.
Good fun though.
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68 and proud! Guessed a few which probably upped my score.
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88% but haven't a clue how you which are right and which are wrong. It told me I was wrong on only one of the questions.
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I never noticed it telling me I was wrong. But I was a bit hasty a couple of times.
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It told me I was wrong on only one of the questions.
I got half way through, answered a question and a box popped up saying "correct!". I thought: was that a special bonus question or have I got them all wrong so far!?
A glitch in the software..
Edited by Rich 9-3 on 24/10/2007 at 18:06
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Scraped pathetically by with 82 memories of napthalene experiments come trickling back,
Enjoyed the test though.
Would like to know how any of our younger say under 30 did on test
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Would like to know how any of our younger say under 30 did on test
I'm 22... scraped a pass - 82% :o)
As soon as I saw "mechanical aptitude" I thoguht ut-oh... but most of the questions were reasonable. I was let down by the weight questions (and star/ring gears - what are they?) but got all the electrical ones right to make up for it.
Oh and by the way, if anyone wants to know which answers they got right or wrong at the end, press the icon that looks like a lopsided pause button labelled "Show/hide TOC" when you scroll over it.
Edited by pendulum on 08/11/2007 at 10:55
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>>That's very well put, mapmaker, if I may say so.
Thank you. The "centrifugal is absence of centripetal" phrase is copyright to RKD who taught me Physics. Thank you Sir.
>>"No such thing as suck"
I don't think I agree. It's all about pressure imbalance. You can either increase the pressure within a piston, or reduce it. The end result is a movement of fluid in order to rectify the imbalance. Suck describes very clearly that the pressure is reduced.
If your pump sucks, it is limited to - what - 12m of water; if it pushes you are limited only by the power of your pump.
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*Smug mode on*
94%
*Smug mode off*
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Modesty prevents me revealing my score - suffice to say I thoroughly approve of the test ;-)
i don't think think the piston question was ambiguous at all - it was essentially , "does the movement of the piston suck the air in or is it pushed in by atmospheric pressure" - it didn't say "is it caused by the movement of the piston".
To illustrate that it is atmospheric pressure, consider the effects of different pressure levels - the amount of air pushed in is greater at higher pressures, even thought the piston movement is the same. Reducto ad absurdum, if no atmospheric pressure, no air movement, regardless of piston antics.
Alternatively, consider the maximum height you can raise a column of liquid to - with a vacuum above it, the height is proportional to the atmospheric pressure - it's that wot does it!
Edited by Manatee on 24/10/2007 at 22:18
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"does the movement of the piston suck the air in or is it pushed in by atmospheric pressure"
If you accept the notion of 'sucking', which is not only popularly understood, but used as part of the question, then both are true. If they wanted to be scientifically correct, they shouldn't have used the term in the first place!
IIRC, the shorthand description of the Otto cycle is 'suck, squeeze, bang, blow'...
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