mechanical aptitude
 

http://www.forddoctorsdts.com/quizze...alAptitude.php

I got 86%


Anyone beat it?

Shame it doesn't tell you which you got wrong.

Re: mechanical aptitude
 

Only 40% lol, it does tell you which you got wrong, you could click on the icon on the left

Re: mechanical aptitude
 

Re: mechanical aptitude
 

I was doing ok but stopped understanding the questions when I got to question 8 - I'm not mechanically minded! :D

Re: mechanical aptitude
 

Re: mechanical aptitude
 

I started doing it but when I saw there were 50 questions I decided I could not be bothered. That and having to sort out stuff tonight for school tomorrow with Rhonda being in hospital over night having her lobotomy reversed.

Re: mechanical aptitude
 

Re: mechanical aptitude
 

I got to about question 5 and couldn't be arsed :)

Re: mechanical aptitude
 

I decided not to bother looking:D

Re: mechanical aptitude
 

I only got 46% so not very good.:(

I'm not good at those sort of questions.

Re: mechanical aptitude
 

82% didnt beat you but passed :)

Re: mechanical aptitude
 

Re: mechanical aptitude
 

You're going to ruin your reputation for being nosey :D:p

Re: mechanical aptitude
 

got 42% which is 40% more than i expected, owt above donkey broke down,n i'm knackered.:D

Re: mechanical aptitude
 

I can see I'm not going to get much response to my question from all you mechanically minded lot! :D

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Re: mechanical aptitude
 

Re: mechanical aptitude
 

I only got 56%. Don't bring your car to me when it goes wrong. :(

Re: mechanical aptitude
 

he he he, you'll do a better job than me westender:D

Re: mechanical aptitude
 

I got 94%

It does tell you which you got wrong and it even got one answer wrong itself. Well not so much wrong as having two correct answers and only selecting one of them as correct and of course the other one became incorrect.

Q48 – In a naturally aspirated engine, air enters the cylinder because of

Their answer – From atmospheric pressure pushing it in.

I selected from suction caused by the piston going down, which is the same thing. In fact it is probably more correct than their answer.

The piston moves down and tries to create a vacuum which is equalised by the air pushing in from outside. If the piston didn’t move down there would be nowhere for the air to rush in. The piston doesn’t move down because of the air rushing in but because the crankshaft is still rotating after ignition and pulls it down, thus creating a vacuum, which is equalised by the air rushing in.

So my score should have been 96%.

Re: mechanical aptitude
 

Wow! Well done, Jambutty.:)

Re: mechanical aptitude
 

Willow, the fact that the three small wheels are teh same size allows it to keep moving. if one was a different size then it would lock up as it would be trying to move faster than teh others which wouldn't be possible. as it is each is trying to move in exactly teh same direction and speed so it 'works'

Re: mechanical aptitude
 

Hey, Cashman, between the 2 of us we got 96%. Maybe if we worked together we could






****** it up completely. :)

Re: mechanical aptitude
 

68% but I am useless at theory so I am suprised. :eek:

Re: mechanical aptitude
 

Re: mechanical aptitude
 

Re: mechanical aptitude
 

I chose suction too and I'm still convinced that is more right than their answer but I can see the logic of 'air pushing into a vacuum' but to my logic air is sucked into a vacuum.

If the outer rim didn't have cogs then I would agree with you Ian, but the cogs in the outer rim are locked into the cogs in those three small 'planetary' wheels which in turn are locked into the central 'sun'. In any series of gears if one of the cogwheels is held rigid then it prevents the movement of any wheel it interlocks with. So I still say they couldn't possibly move. Now if that outer rim was smooth then of course the three planetary wheels would slide effortlessly within it and their answer would apply, but the rim in the image is not smooth.

Re: mechanical aptitude
 

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:eek: That's decided it - I'm definately not gonna look:eek:

Re: mechanical aptitude
 

agree with you on this , that was my thought (seized up gearbox)

Re: mechanical aptitude
 

You need to understand what suction is to see why they asked the question and why they gave the answer they did. Suction - Wikipedia, the free encyclopedia

Re: mechanical aptitude
 

If the piston didn't move their would be nowhere for the air to go. So we were right and they were not wuite so right.

The outer rim doesn’t have cogs – it is itself a cog and it is locked.

The sun may be fixed on its axis but the planets are free to move rotationally and laterally.

Re: mechanical aptitude
 

This explains the gears a little better willow. Look how the outer gear is part of the gearbox casing so is held stationary. the 3 inner gears are fastened on a common plate and to the output shaft.

Epicyclic gearing - Wikipedia, the free encyclopedia

Re: mechanical aptitude
 

If you have two containers of differing air pressure and they are connected the air pressure will equalize in both. Whether it is sucked in or pushed in is a moot point and dependant on whether you are in one container or the other. If you are in the low pressure container the air is being sucked in. If you are in the high pressure container the air is being pushed out and if it is being pushed out of one it can be said to be pushed into the other.

It’s a bit like when you mix hot and cold water. Does the hot water make the cold water warmer or does the cold water make the hot water cooler.

The bottom line is that it is the movement of the piston that creates a vacuum and this vacuum sucks in the air. If the piston did not move the air from outside would not push it down.

Re: mechanical aptitude
 

Re: mechanical aptitude
 

:D

I too went suction mainly as Jambutty said, the initial action that caused the movement of air is the piston going down. hence as it instigated the whole proceeding I reckon suction is right. Atmospheric pressure was only equalling the pressure so it wasn't pushed in as all,it was dragged across. To me pushed infers that 'positive pressure' is in action.

Well Done Jambutty though!

The ones that made me think were the multiple pully ones.

Re: mechanical aptitude
 

Re: mechanical aptitude
 

It depends where you are. In the cylinder you have negative pressure relative to outside it, outside the engine you have positive pressure relative to inside it. The air will move from a high pressure area to a low pressure one. That is why the air is pushed in. It's still works the same way in a turbo charged car.

You would not say the air is sucked out of you tyre when you press the valve in. The air will move from the high pressure inside the tyre to the low pressure outside. The word suction is commonly used when pressures under 1 bar are involved.

In the end it comes down to using the scientifically correct words. As in a bulb is where daffodils come from whereas light comes from a lamp. It does not really matter which way you describe it. They put that question in to catch people out.

I was discussing this with my mate, an ex fireman. He said they were always taught that if you are pumping water from a pond, the pump does not suck the water out of the pond. Atmospheric pressure acting on the surface of the pond pushes the water into the low pressure area created in the pumps inlet pipe.

The input to a pump is commonly known as the suction side and the output is known as the pressure side. That's stupid English language for you.

Re: mechanical aptitude
 

I got 42%........

Re: mechanical aptitude
 

Re: mechanical aptitude
 

Ah! Yes! The multiple pulleys. That got my brain cell agitated a bit too but I got it right.

I got the electric fan question wrong and I’m damned if I can remember which was the other one.

What I can say is if the text were timed I wouldn’t have done so well. I don’t think quite as fast as I used to.

Air will always try to equalise if two connected containers have a different psi Neil. Whether you consider it pushing the air from high to low or pulling (sucking) the air into the low from the high isn’t really relevant.

When you withdraw blood from a vein does the hypodermic withdraw (suck) the blood out or is the heart pumping it out? You can still withdraw blood from a dead body therefore the blood is sucked out.

Re your analogy of the fireman’s water pump. You can still pump water out of a sealed container where air is prevented from replacing the removed water. It takes more effort but it can still be done. Therefore the water is sucked out.

I think that answer is to agree to differ on this issue but so far with three people opting for sucking against one person opting for pushing, the suckers have it.

Re: mechanical aptitude
 

They do WillowTheWhisp.

But did you know that you can get compressed air to act just like a vacuum cleaner?

Take a long tube and part way down attach another tube to it at an angle. A bit like a capital Y. Blow air down the left hand part from top to bottom and it will suck air down the right hand part from top to bottom. It is quite a powerful suction too.

Re: mechanical aptitude
 

No blood is not sucked out of a dead body. You create a low pressure in the syringe, the body is at atmospheric pressure, so the blood moves to the low pressure in the syringe.

Re: mechanical aptitude
 

But it doesn’t push the syringe plunger to create the vacuum. The nurse does that by pulling the plunger.

At some time in your life, surely you must have seen a nurse take a small bottle of sterilised water, stick a hypodermic needle into it through the rubber seal, draw off some of the water and transfer it to another bottle that holds the medication that will be injected into someone. There is no air in the bottle of sterilised water so the water must be sucked out.

According to the Oxford English Dictionary:
• verb 1 draw into the mouth by contracting the lip muscles to make a partial vacuum.
2 hold (something) in the mouth and draw at it by contracting the lip and cheek muscles.
3 draw in a specified direction by creating a vacuum.

Nothing to say about:
Re your analogy of the fireman’s water pump. You can still pump water out of a sealed container where air is prevented from replacing the removed water. It takes more effort but it can still be done. Therefore the water is sucked out.

The definition of a Suction Pump
Noun - a pump for raising fluids by suction
http://uk.ask.com/reference/dictionary/wordnetuk/178384/suction%20pump

Attach a vacuum pump to a bell jar and set it going. It will be sucking the air out of the bell jar.

Basically it amounts to - when you remove air or a liquid from somewhere you suck it out. When you put air or liquid into a container of some sort you pump it in.

Re: mechanical aptitude
 

I got 50% 250 points. Okay i failed seeing as the passing percent is 80 but im happy with that seeing as im not mechanically minded even though i worked for an engineering company that made axles and worked in a fitting shop for a bus company! But it does show that i did pick something up otherwise it would have been worse.

Re: mechanical aptitude
 

How many times do I have to say, the movement is from an area of high pressure to an area of low pressure?

Re: mechanical aptitude
 

In fact the title of the article is interesting because, as it mentions, a vacuum cleaner will not work on the moon.

Here is a quote from this teaching website Workbench: You Can’t Vacuum the Moon

Your comments about liquids are also incorrect. It is the pushing force of gasses that cause the movement of liquids in all the cases that have so far been mentioned. Unless of course you are pressurising the liquid then it too will move from an area of high pressure to one of low pressure ( a hose pipe would be a simple example)

If you don't want to believe what it says that is fine by me. I am surprised by the way you let your stubbornness make you appear ignorant to the physics in question. I must have been wrong when I assumed you to be an intelligent man.

Re: mechanical aptitude
 

No one ever stated that you could vacuum on the moon. But then that is what some people do, throw in red herrings to confuse the issue.

But you can pump water on the moon if there is enough of it to pump before it evaporates. Which totally destroys your theory that it is air pressure on the surface of the water that forces the water through a pump and not the pump sucking the water away. There ain’t no air on the moon.

And you have conveniently forgotten to challenge the ‘air is sucked out of a bell jar by a vacuum pump’ statement. Could it be that there is no challenge to make and you cannot bring yourself to admit that air and water can be sucked out from containers as well as being pumped out?

However if the best that you can do is insult people there is no more to be said.

Verb sap!

Re: mechanical aptitude
 

Insult you, I actually paid you a complement.

I have given you a link explaining how suction really works but you choose to ignore it. What else can I say to that? Unfortunately you appear unable to admit when you are wrong, I can say that is a quality that I do poses and if you took of your blinkers and actually read the link I posted you should now understand why I have been saying what I have all along. Unless of course my Physics A level teacher was also wrong :rolleyes: