Was posted in alt.machines.cnc... But doesn't seem to have migrated over here yet...
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:Joe AutoDrill wrote: : Was posted in alt.machines.cnc... But doesn't seem to have migrated over : here yet...
:
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
470, but 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. To get their answer you have to assume a point mass, that's a pretty tenuous stretch of the imagination. Redrawing the diagram a little better would clarify things.
Anyone found the full set of correct answers yet? I'm too busy just at the minute, but it would be interesting to see them.
I agree with Chip on Q31. But by his (and my) analysis, none of the answers given were correct.
--Steve
Fun little test. I got 480.
Their answer to #16 is wrong. Since the ropes are angled somewhat the actual force would be more than 50kg. (And besides, kg are a unit of mass, not force. The actual force would be a bit more than 9.8 * 50 Newtons.)
I too think their answer in #31 is wrong, and some of their electrical symbols are a bit funky.
I got wrong the pipe one wrong. I expect that Bernoulli's principle means that the pressure is lower in the narrower section.
I also got the "naturally aspirated engine" one wrong. I said it was suction from the piston, but really that wouldn't cause anything to happen without atmospheric pressure pushing it in, so I guess I can't complain.
Chris
I got a 480.
Right, the correct answer is 60. Not seeing that as an option, I figured out how they measured it and chose their answer.
Also the question about naturally aspirated pistons was ambiguous. There were two correct answers, depending on your point of view. The retreating piston creates a lower pressure inside the cylinder, but one could argue that both the retracting piston *and* the natural atmospheric pressure work together to force air into the cylinder. They marked that one wrong, but I knew I had a 50/50 chance.
I got the balloon one wrong, but I think they're wrong, or at least ambiguous. For the baloons to be different sizes in the same air space (as shown), they have to be of different composition, so they all are in the "same air" and thus atmospheric pressure (PSI) is the same (14psi at sea level, for example) but the balloons themselves exert varying pressures on the gasses therein. Had they asked which had the highest pressure INSIDE the balloon, I would have gotten their answer. Unless they meant TOTAL pressure exerted by the atmosphere, in which case they should have asked for that (and in which case, the contents of the balloons is irrelevent). Or if they assume the balloons have not yet reached steady state, but that wasn't mentioned in the problem either.
Or maybe I was just over-analyzing it. The picture does show them in common air, though. Had they drawn lines between the balloons, to show them possibly in different air pressures, I would have gotten it right.
After you're done, you can review the results and see the right answers, and which you got wrong. Use the poorly-labeled magnifying glass icon.
Same score and comment on Q31 as Steve. Kerry
490. I'd like to know which question I missed....
There is some little clickable thing at the bottom that reveals which you missed.
Ditto in score (480) and ditto in complaints. Without the piston creating a (partial) vacuum, the atmosphere could NOT push in the air....and the piston down. Got the pipe one wrong too.
Without an atmosphere, there would be no vacuum. :)
When you can see the results, it's easier...
Q7 (which geartrain is which) is just plain wrong. Even allowing for crazy Yankee terminology, there's no way that the one train of three pinions (the others are all 2) can be "reverse". That's not mechanical aptitude, that's assuming that you're looking inside a RWD car gearbox (where the extra idler gear is indeed used for reverse) -- but then "direct drive" in that context wouldn't be using any of the gears.
Q45 The balloons are another bad question. Three balloons illustrated as being next to each other? Of course the atmospheric pressure is identical (Pascal's principle, if you care), it's far more likely that they're made of thicker rubber than there's some sort of barometric change across the page.
missed the planetary gear direction, matching up the description (reverse, reduction, etc.) with the gear pictures, and the fan blowing on the fan.
Tom Veatch Wichita, KS USA
Agree! To get an answer that is listed, you have to assume the CG of each box is at the outer edge of the box..
Tom Veatch Wichita, KS USA
480
I agree. They are the two I got wrong.
"Joe AutoDrill" wrote in news:9ToTi.1289$Gq2.470@trnddc01:
Well, I didn't do that great. 370.
I missed many of the same questions others did, and messed up a few on my own. The ones I did mess up where the ones involving some math (and physics) mainly because I just half guessed.
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
420 , not bad for an offcie worker.
Missed:
#7. I reversed their opinion of the direct vs reversing drive. I picked C as the reversing drive since the two gears go in the opposite direction. I am a EE so I admit ignorance about the choice of terminology. I still like my choices better.
#11. The screw drive I am probably wrong (see previous comment about being an EE).
#31. I also agree that the correct answer should be 60. I picked 50 as being the closest. The only way that 100 would be correct if the weights are a point mass and the mass is at the outside edge of each box.
#38. This one is ambiguous. Since the two fans are facing in opposite directions, what frame of reference should be used? I chose that the unpowered fan will be going in reverse (compared to what it would be going if it had power applied).
#44. Another ambiguous question. I finally chose C (in tube A only). I had initially selected A (higher in tube A then tube B) but changed to C. As mentioned by another poster. This is a venturi tube. The height in tube B will definitely be lower than tube A. Whether there is any water in tube B depends upon the outlet pressure at the right. I guessed that they wanted C. After I went to the next question. I reconsidered since A would be technically more correct. However getting the answer correctly on a test involves guessing what is expected by the people creating the test. I guessed wrong.
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