"Chip Buchholtz" wrote in message
...
Joe AutoDrill wrote:
: Was posted in alt.machines.cnc... But doesn't seem to have migrated
over
: here yet...

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

: I scored a 430...

I scored a 420, and I think their answer for question 31 is wrong. I
measured from the center of gravity of the load to the fulcrum, and
they measured from the outer edge of the load to the fulcrum.

I emailed them about it, so I'll probably find out that I screwed up.

It's a fun quiz, thanks!

--- Chip

It is a fun quiz, I scored a 460 - 92%.

"Joe AutoDrill" wrote in
news:k5tTi.1314$Gq2.864@trnddc01:

Such as the intake stroke bringing air in. Air pressure is the
correct answer but 'suction' should also be correct, by definition.

Someone said that suction can't exist without air in the first place.


Fun little time waster though, eh?

Regards,
Joe Agro, Jr.

They are mutually dependant, or IOW, one cannot exist without the other.
Thus, both answers are right.

Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

Tom Veatch wrote in :

On 23 Oct 2007 20:19:34 GMT, Puckdropper
wrote:

I'm not sure about the question with the three lights and switch
bypassing one. They're going off a common misconception that
electricity follows the path of least resistance, but that cannot be
true. Parallel circuits would NOT work if it was. If I remember,
I'll test it on a breadboard later.

Puckdropper


The current in each branch of the parallel paths will be inversely
related to the resistance of the branch and directly related to the
resistance of the parallel branch. You can use Ohm's law (E=IR) to
derive the mathematical relationship.

If you assume the path through the switch has zero resistance (an OK
first approximation) then the current through the lamp would be zero.
As the resistance of the path through the switch increases, the amount
of current through the lamp would increase.

If you breadboard it, insert a variable resistor in series with the
switch. I predict that as you increase the resistance of the path
through the switch, the brightness of the lamp will also increase.

Tom Veatch
Wichita, KS
USA

That makes a LOT more sense. I'll have to breadboard it to see what
actually happens...

Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

Puckdropper writes:
That makes a LOT more sense. I'll have to breadboard it to see what
actually happens...

Even if the switch has a non-zero resistance, the voltage across it
and the light will be so low that the bulb won't have enough power to
produce any visible light.

But to simplify...

Consider each bulb has a 10 ohm resistance, and it's a 10 volt
battery. One light = one amp. Two lights in series = 20 ohms = 0.5
amps, which each light sees. Two lights in parallel = 5 ohms = 2
amps, split between the lights = 1 amp each. Assume the switch is
0.01 ohms (they're usually much less).

So with one bulb in parallel with the switch, and a second in series
with those two, the MOST current you'll get is 1 amp (just the second
light alone limits it to that). If the switch is closed, 1 amp
through it is 0.01 volts. That's the most voltage that will be across
the switch/light combo. 0.01 volts divided by 10 ohms (the first
light) gives 0.001 amps (1 milliamp), far less than the 1 amp it's
expecting.

To figure exact values, consider:

V1 V2
*---\/\/\/\----+-----\/\/\/\/----+ 0v
-- R1 | R2 |
I +-----\/\/\/\/----+
R3 |
---

R2 and R3 in parallel give 1/(1/R2+1/R3) ohms. Let's call this R23.

V1 V2
*---\/\/\/\----+-----\/\/\/\/----+ 0v
-- R1 R23 |
I |
|
---

Total resistance between V1 and 0v (ground) is thus R1+R23.

Current is V1/(R1+R23). Call this I.

Voltage at V2 (relative to 0v) is I*R23

Current through R2 is V2/R2.

Current through R3 is V2/R3.

For our simplified example, rounded to three sig digits...

V=10 R1=10 R2=10 R3=0.01

R23 = 1/(1/10 + 1/0.01) = 0.00999 ohms
I = 10/(10+0.00999) = 0.999 amps
V2 = 0.999 * 0.00999 = 0.00998 volts
Current through R2 = 0.00998 / 10 = 0.000998 amps
Current through R3 = 0.00998 / 0.01 = 0.998 amps

On Tue, 23 Oct 2007 15:59:01 GMT, "Joe AutoDrill"
wrote:

Was posted in alt.machines.cnc... But doesn't seem to have migrated over
here yet...

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

I scored a 430...

I've got the unfair advantage over some of you of being trained here on the
job... But never had schooling in most of this so...

Share your score with us... No shame or bragging rights, just a fun test.

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R



One of the more interesting challenges that's been posted!

I scored 460.

John

"Joe AutoDrill" wrote in message
news:9ToTi.1289$Gq2.470@trnddc01...
Was posted in alt.machines.cnc... But doesn't seem to have migrated over
here yet...

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

I scored a 430...

I've got the unfair advantage over some of you of being trained here on
the
job... But never had schooling in most of this so...

Share your score with us... No shame or bragging rights, just a fun test.

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R

====== Got a 470. Good test!

Leif

On Tue, 23 Oct 2007 16:54:03 -0400, "HDRDTD"
wrote:

This one triped up every engineer here that has taken the test so far.

I was thinking along the same lines at first, noting that if you measure
from the center of each box to the fulcrum, the the distance ratio appears
to be 5:1 but that results in an answer of 60kg, and that ain't an option
given.

However....

If you look at it as each box sites on two segments, and count that way, or
in other words if each segment was shown as the width of a box, the the
ratio appears as 3:1 which provides the correct solution.



I found this question doesn't have a correct answer. This is a simple
"moment arm" calculation. The center of gravity of the weight to the
fulcrum. In real life, the board itself must be considered, and it,
too, has a moment arm. "60kg" is correct but not a choice.

On Wed, 24 Oct 2007 00:12:15 -0000, Robatoy
wrote:

On Oct 23, 8:04 pm, (Doug Miller) wrote:
In article , Tom Veatch wrote:

missed the planetary gear direction, matching up the description
(reverse, reduction, etc.) with the gear pictures, and the fan blowing
on the fan.

The fan blowing on the fan is an ambiguous question. They're facing each
other, and spinning the "same" direction, in the sense that when viewed from
the side, they're both spinning down on the edge facing you (or up, depending
on which side you're on). But when each one is viewed from *its*own* front,
one is spinning clockwise, and the other counterclockwise.

So is that the same direction? Or the opposite direction?

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Both blades rotate in the same direction regardless of vantage point.
You stand behind one fan, and both blades turn clockwise. You stand
behind the other, both blades turn anti-clockwise. What on earth is so
hard about that, oh wise one?


The confusion is "same direction" and where the observer stands when
evaluating the direction of each fan. Part of this test is
understanding the question. I should have got a perfect score with my
background and education, but did not. I excel at engineering and
math, but English comprehension is another story.

John Cochran wrote:

490. I'd like to know which question I missed....

While working on the test, you can click on the circle with two
rectangles in the lower left area.

Good score!

Phisherman wrote:
On Wed, 24 Oct 2007 00:12:15 -0000, Robatoy
wrote:

On Oct 23, 8:04 pm, (Doug Miller) wrote:
In article , Tom Veatch wrote:

missed the planetary gear direction, matching up the description
(reverse, reduction, etc.) with the gear pictures, and the fan blowing
on the fan.
The fan blowing on the fan is an ambiguous question. They're facing each
other, and spinning the "same" direction, in the sense that when viewed from
the side, they're both spinning down on the edge facing you (or up, depending
on which side you're on). But when each one is viewed from *its*own* front,
one is spinning clockwise, and the other counterclockwise.

So is that the same direction? Or the opposite direction?

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.
Both blades rotate in the same direction regardless of vantage point.
You stand behind one fan, and both blades turn clockwise. You stand
behind the other, both blades turn anti-clockwise. What on earth is so
hard about that, oh wise one?


The confusion is "same direction" and where the observer stands when
evaluating the direction of each fan. Part of this test is
understanding the question. I should have got a perfect score with my
background and education, but did not. I excel at engineering and
math, but English comprehension is another story.

You could look at it this way: The fan that is running is turning in its
normal direction, and the fan that is not running is turning opposite of
its normal direction. Therefore, they are turning in opposite
directions. This reasoning makes the most sense to me, because it takes
point of view totally out of the equation.

In article , "Charlie M. 1958" wrote:
Phisherman wrote:
On Wed, 24 Oct 2007 00:12:15 -0000, Robatoy
wrote:

On Oct 23, 8:04 pm, (Doug Miller) wrote:
In article , Tom Veatch wrote:

missed the planetary gear direction, matching up the description
(reverse, reduction, etc.) with the gear pictures, and the fan blowing
on the fan.
The fan blowing on the fan is an ambiguous question. They're facing each
other, and spinning the "same" direction, in the sense that when viewed from
the side, they're both spinning down on the edge facing you (or up, depending
on which side you're on). But when each one is viewed from *its*own* front,
one is spinning clockwise, and the other counterclockwise.

So is that the same direction? Or the opposite direction?

Both blades rotate in the same direction regardless of vantage point.
You stand behind one fan, and both blades turn clockwise. You stand
behind the other, both blades turn anti-clockwise. What on earth is so
hard about that, oh wise one?


The confusion is "same direction" and where the observer stands when
evaluating the direction of each fan. Part of this test is
understanding the question. I should have got a perfect score with my
background and education, but did not. I excel at engineering and
math, but English comprehension is another story.

You could look at it this way: The fan that is running is turning in its
normal direction, and the fan that is not running is turning opposite of
its normal direction. Therefore, they are turning in opposite
directions. This reasoning makes the most sense to me, because it takes
point of view totally out of the equation.

But according to the testmakers, that's the "wrong" answer. :-)

Without knowing what frame of reference is intended by the testmaker, it's not
possible to determine which answer is "correct".

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Without knowing what frame of reference is intended by the testmaker, it's
not
possible to determine which answer is "correct".

The test is probably written buy guys who can score a 100% on tests like
that... Which means they are engineers who didn't think through the process
as beta testers.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R

On 24 Oct, 13:56, (Doug Miller) wrote:

Without knowing what frame of reference is intended by the testmaker, it's not
possible to determine which answer is "correct".

The obvious frame of reference for a question would be that of the
overall question, i.e. "same" means that the fans rotate such that
they don't have a blade speed relative to each other. If we were a fan
shop, then we might well regard "same" differently, as meaning that
they're both clockwise when reading the maker's plate.

Unfortunately thhis common and sensible convention is then defeated by
the balloons question. That only makes sense if we regard each balloon
as being in a separate system.

On Oct 23, 11:59 am, "Joe AutoDrill" wrote:
Was posted in alt.machines.cnc... But doesn't seem to have migrated over
here yet...

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

I scored a 430...



Please, if we can't see the answer sheet, don't recommend the test.

I went and took it, got 400, but was disappointed in not having an
opportunity to know which questions i got "right" according to thier
proctor.

Reading the responses here, it would appear that I share some of
"folk's" concerns relative to the design of the test.

I hate to count gear teeth (they could have done that for us with
labels.

I should have eaten breakfast instead

I've got the unfair advantage over some of you of being trained here on the
job... But never had schooling in most of this so...

Share your score with us... No shame or bragging rights, just a fun test.

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills:http://www.AutoDrill.com
Multiple Spindle Drills:http://www.Multi-Drill.com

V8013-R

Hoosierpopi writes:
Please, if we can't see the answer sheet, don't recommend the test.

You can see the answer sheet. Read the past posts; there are at least
two ways to do so. Of course, finding them is part of the test ;-)

In article .com, Hoosierpopi wrote:
On Oct 23, 11:59 am, "Joe AutoDrill" wrote:
Was posted in alt.machines.cnc... But doesn't seem to have migrated over
here yet...

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

I scored a 430...



Please, if we can't see the answer sheet, don't recommend the test.

There's a "review" button at the end. Not especially obvious, but it's there.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Please, if we can't see the answer sheet, don't recommend the test.

Look harder next time. Sounds like your frustration caused you to miss the
small clickable link that brought up the answer sheet.

I went and took it, got 400, but was disappointed in not having an
opportunity to know which questions i got "right" according to thier
proctor.

ibid.

Reading the responses here, it would appear that I share some of
"folk's" concerns relative to the design of the test.

Yep. Same with me... But it wasn't a "real" test so I'm not going to gripe
about it too much.

I hate to count gear teeth (they could have done that for us with
labels.

And they could have put the ratio below the gears too... I think being able
to properly count is part of the test IMHO.

I should have eaten breakfast instead

I guess that all depends on what you would have eaten...
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R

DJ Delorie wrote:

You can see the answer sheet. ---- Of course, finding them is part of the test ;-)

That was my EXACT thought. G

"Men in Black" style...

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.

(Doug Miller) wrote in
et:


There's a "review" button at the end. Not especially obvious, but it's
there.


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

Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

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:

Was posted in alt.machines.cnc... But doesn't seem to have migrated over
here yet...

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

I scored a 430...

I've got the unfair advantage over some of you of being trained here on the
job... But never had schooling in most of this so...

Share your score with us... No shame or bragging rights, just a fun test.

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R

On Oct 23, 11:59 am, "Joe AutoDrill" wrote:

Just love those kind of tests. They illustrate, to me, that people
like me, who do well, are people who are cynical enought to anticipate
semantics. The answers fall into two categories:
What do they want?
and
What is right?

Some of these questions fall into the category of:
Have you stopped beating your wife?

Sometimes there is no right answer and the questioner has to be taken
to task.

In any classroom I have ever taught, I would have been murdered by my
students simply becaue the ambiguity of half of those questions.

So:
Has you mother ever caught you masturbating?

WoodWizzard wrote:
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:

Was posted in alt.machines.cnc... But doesn't seem to have migrated over
here yet...

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

I scored a 430...

I've got the unfair advantage over some of you of being trained here on the
job... But never had schooling in most of this so...

Share your score with us... No shame or bragging rights, just a fun test.

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R

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

On Wed, 24 Oct 2007 07:40:54 -0500, "Charlie M. 1958"
wrote:


You could look at it this way: The fan that is running is turning in its
normal direction, and the fan that is not running is turning opposite of
its normal direction. Therefore, they are turning in opposite
directions. This reasoning makes the most sense to me, because it takes
point of view totally out of the equation.

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

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

On 24 Oct 2007 17:56:40 -0700, wrote:
....
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


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

On 23 Oct, 18:14, Andy Dingley wrote:

I wasn't impressed by some of the questions. As an example,
the "two boxes on a seesaw" has a range of possible answers, depending
on whether they're a point mass or a distributed mass within the box.

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-(

"Robatoy" wrote in message
ps.com...
On Oct 23, 11:59 am, "Joe AutoDrill" wrote:

Just love those kind of tests. They illustrate, to me, that people
like me, who do well, are people who are cynical enought to anticipate
semantics. The answers fall into two categories:
What do they want?
and
What is right?

Some of these questions fall into the category of:
Have you stopped beating your wife?

Sometimes there is no right answer and the questioner has to be taken
to task.

In any classroom I have ever taught, I would have been murdered by my
students simply becaue the ambiguity of half of those questions.

So:
Has you mother ever caught you masturbating?


See all those hairy palms waving?

The best way I've found to deal with ambiguity is to ask myself "how would I
answer this if I were an idiot?" Works most every time, though sometimes
all are so ridiculous that I have to fall back to option B and go with the
longest answer.

Even works on non-government tests, as my molecular Biology prof learned
when I showed him the longest answer rule on his tests. I let him off with
a six-pack of domestic.

In article 9ToTi.1289$Gq2.470@trnddc01,
Joe AutoDrill wrote:
Was posted in alt.machines.cnc... But doesn't seem to have migrated over
here yet...

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

I scored a 430...

I've got the unfair advantage over some of you of being trained here on the
job... But never had schooling in most of this so...


Yawn. 480

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

In article ,
Doug Miller wrote:
In article , "HDRDTD"
wrote:
This one triped up every engineer here that has taken the test so far.

I was thinking along the same lines at first, noting that if you measure
from the center of each box to the fulcrum, the the distance ratio appears
to be 5:1

Not "appears to be". Is.

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??

Robert Bonomi wrote:
In article ,
Doug Miller wrote:
In article , "HDRDTD"
wrote:
This one triped up every engineer here that has taken the test so far.

I was thinking along the same lines at first, noting that if you measure
from the center of each box to the fulcrum, the the distance ratio appears
to be 5:1
Not "appears to be". Is.

HUH???

I see two triangles point down.
....

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...

--

Robert Bonomi wrote:
: In article ,
: Doug Miller wrote:

: 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

In article . com,
Robatoy wrote:
On Oct 23, 8:04 pm, (Doug Miller) wrote:
In article , Tom Veatch wrote:

missed the planetary gear direction, matching up the description
(reverse, reduction, etc.) with the gear pictures, and the fan blowing
on the fan.

The fan blowing on the fan is an ambiguous question. They're facing each
other, and spinning the "same" direction, in the sense that when viewed from
the side, they're both spinning down on the edge facing you (or up, depending
on which side you're on). But when each one is viewed from *its*own* front,
one is spinning clockwise, and the other counterclockwise.

So is that the same direction? Or the opposite direction?

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Both blades rotate in the same direction regardless of vantage point.
You stand behind one fan, and both blades turn clockwise. You stand
behind the other, both blades turn anti-clockwise. What on earth is so
hard about that, oh wise one?


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.

In article , (Robert Bonomi) wrote:
In article ,
Doug Miller wrote:
In article , "HDRDTD"
wrote:
This one triped up every engineer here that has taken the test so far.

I was thinking along the same lines at first, noting that if you measure
from the center of each box to the fulcrum, the the distance ratio appears
to be 5:1

Not "appears to be". Is.

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??

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.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Robert Bonomi wrote:
In article . com,
Robatoy wrote:
On Oct 23, 8:04 pm, (Doug Miller) wrote:
In article , Tom
Veatch
wrote:

missed the planetary gear direction, matching up the description
(reverse, reduction, etc.) with the gear pictures, and the fan
blowing on the fan.

The fan blowing on the fan is an ambiguous question. They're
facing
each other, and spinning the "same" direction, in the sense that
when viewed from the side, they're both spinning down on the edge
facing you (or up, depending on which side you're on). But when
each one is viewed from *its*own* front, one is spinning
clockwise,
and the other counterclockwise.

So is that the same direction? Or the opposite direction?

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Both blades rotate in the same direction regardless of vantage
point.
You stand behind one fan, and both blades turn clockwise. You stand
behind the other, both blades turn anti-clockwise. What on earth is
so hard about that, oh wise one?


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.

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.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)