Mechanical Aptitude Test

Scored 480, missed two questions.

(Sorry if this post gets duplicated but it didn't go through the first time I submitted it)

The question about the normally aspirated engine I believe was ambiguous. I wasn't sure whether to pick atmospheric pressure, or vacuum created by the piston as the reason for their being airflow. The reason being that the airflow is a result of the pressure differential between the atmosphere and that inside the cylinder, so either of those two choices by themselves is really only half the answer. I more or less randomly picked the vacuum answer since it seemed more a specific aspect of an engine - but that was the wrong one :-)

In fact, the other multiple choice answer "gravity" plays a factor in the whole thing too since there would be no atmosphere if there were no gravity :-) Gravity also produces the atmospheric pressure as well.

The other one I missed was the one with the gear drive train. I knew which direction and what (relative) speeds the gears were spinning but was not familiar with the terminology of the labels.

Reply to
somewildmonkey
Loading thread data ...

snipped-for-privacy@milmac.com (Doug Miller) wrote in news:NOITi.13601$ snipped-for-privacy@newssvr27.news.prodigy.net:

If you found the review button, add 10 points to your score. :-)

Puckdropper

Reply to
Puckdropper

Not bad for an "Old Mechanic" who learned from the school of hard knocks, and my Dad. I started pulling wrenchs at the age of 5 in my Dad's shop.

Score of 460 %92

Joe AutoDrill wrote:

Reply to
WoodWizzard

Wow! Sorry, but had to brag a bit here. No schooling in any of this, except a bit in electricity. I got 440! WTF? Sure didn't expect that!

Harvey

Reply to
eclipsme

That's exactly the way I looked at it - in terms of each fan - which is why I "missed" the question. Too ambiguous and ill-defined. I think I'll award myself another 10 points because I had the physics/aerodynamics right, but flunked the "mind-reading" part of the question.

OK, now I'm up to 480.

Tom Veatch Wichita, KS USA

Reply to
Tom Veatch

Scored 480.

I missed the one regarding the normally aspirated engine. I thought long and hard about it because I considered it ambiguous. I know this has been discussed here but this is my take:

The airflow is not caused just by atmospheric pressure alone, nor by the vacuum created within the cylinder alone. It's the differential in pressure which causes the airflow. So, to me, although neither of those two choices were precise, it had to be one or the other. I guessed wrong :-)

For that matter, you could even say it's caused by gravity since without gravity there would be no atmosphere nor atmospheric pressure :-) So the answer should really be (a)(b) and (c)

The other one I missed was the one with the various drive train components. I knew which way all the gears were spinning but had trouble with the terminology of the labeling.

- MB

Reply to
somewildmonkey

On 24 Oct 2007 17:56:40 -0700, snipped-for-privacy@yahoo.com wrote: ...

Agree! And, that makes the test (or at least that question) invalid for measuring aptitude. Perhaps it would be valid as an exit exam after a course of instruction in which terminology/jargon was defined, but not as an entrance exam prior to exposure to the jargon.

(I missed that one, too. So maybe the above is just a little sourness in the grapes.)

Tom Veatch Wichita, KS USA

Reply to
Tom Veatch

If you look back now, you'll see that they've changed the seesaw question in the test! Maybe the authors are reading this newsgroup?

OTOH, the change they've made (triangular boxes) is farcical and shows that they really don't understand the issue that was raised 8-(

Reply to
Andy Dingley

Yawn. 480

Both the ones I missed are written so badly that it is very arguable as to what the right answer is..

Reply to
Robert Bonomi

HUH???

I see two triangles point down. center of mass _is_ the same as the point of contact with the lever. The lever is already marked in uniform segments.

The one on the left is _two_ segments out from the fulcrum The one on the right is _six_ segments out from the fulcrum.

How in name of {something} do you come up with anything other than 3:1??

Reply to
Robert Bonomi

...

They changed the pictures from boxes from the time the initial takers in the thread visited the quiz so you're looking at a different problem than the one under discussion...

--

Reply to
dpb

: I see two triangles point down. : center of mass _is_ the same as the point of contact with the lever. : The lever is already marked in uniform segments.

: The one on the left is _two_ segments out from the fulcrum : The one on the right is _six_ segments out from the fulcrum.

: How in name of {something} do you come up with anything other than 3:1??

Aha! They got my message and fixed the question!

It used to be two squares, and the answer they wanted was based on the

*outer* edge of each square, not the center. I suggested that using triangles or circles would make it easier to see where the center of mass was; you wouldn't have to decide between the inner edge, the center, or the outer edge.

--- Chip

Reply to
Chip Buchholtz

It's a matter of viewpoint. the question is BADLY worded.

If both fans were turning in the 'same' direction,, both would be pushing air from back-to-front of the fan.

one fan is turning 'forwards' the air is travelling from back to front of that fan.

The other fan is turning 'backwards' the air is traelling from front to back of thhat fan.

Considered from a single external viewpoint, both are rotati in the same diretion.

Considered from the view point of the motor on each fan, for _that_ fan, they are rotatig in different diretion.

The issue is whether the fan 'reverses diretion of rotation' just beause you point it in a different diretion.

*GENERALLY* shaft rotation is measured relative to the motor, indepedant of absolut orientation in space.
Reply to
Robert Bonomi

Simple: they changed the picture between then and now, presumably in response to numerous complaints that their answer was wrong. At the time HDRDTD and I posted, the picture looked something like this (view in a fixed-space font):

___ ___ | | | | |___| |___|

-- -- -- -- -- -- -- -- /\ /__\

As illustrated, the centers of mass are at 1 unit, and 5 units, distant from the fulcrum.

Reply to
Doug Miller

They really should have just done the same thing they did with their first rotation question--have two arrows and you pick which one points the direction of rotation.

Reply to
J. Clarke

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.