Neat mechanical aptitude test

[Honclfibr]

The assumptions made in the electrical question would be implied by the fact that there are no units given for anything. It's kind of a basic premise of circuit analysis that switches and wires are zero resistance, and lamps are nonzero resistance. This is not the case, but it's necessary for solving those sort of problems. Sort of like assuming all beams are rigid for the purposes of solving a statics problem.

[RyanNicholson]

i got an 86% haha....i'm actually pretty proud of myself.

thats a really cool lil test, nice find!

[978chris]

More importantly, I like to be difficult and question things, because that is my job (and I'm a PIA )

I'm the same way. Seriously, people at work are like "who cares just do it" and I am like "I fucking care, I don't like to fail"... In the end I cause more work for everyone but the shit gets done better than it would've. They hate me but I have personal satisfaction when I look at my work. It's a shitty balance.

[ZX-12R]

Edit: Fuck. Beatened.

I ninja deleted my post because I wanted to add more detail to it but then I noticed you answered as well.

[hammadown]

The answer to the question is correct and your reasoning is a bit off. PV=nRT is not applicable in this example because V and T refer to the volume and temperature of the container that the gas is contained in and not the gas itself.

The correct formula you need to apply is:

(P1^(1-k))*(T1^k) = (P2^(1-k))*(T2^k)

where:

P1 = initial pressure
T1 = initial temperature
P2 = final pressure
T2 = final temperature
k = heat capacity ratio (Cp/Cv: Air is about 1.4)

This formula assumes that the vessel is not absorbing heat from the process(adiabatic).

Oh damnit, you're right. PChem was so long ago. Don't listen to me, I am a moron. Ill just stick to playing with my big magnets...

[978chris]

The assumptions made in the electrical question would be implied by the fact that there are no units given for anything. It's kind of a basic premise of circuit analysis that switches and wires are zero resistance, and lamps are nonzero resistance. This is not the case, but it's necessary for solving those sort of problems. Sort of like assuming all beams are rigid for the purposes of solving a statics problem.

Yeah I always get in arguments with my step mom (calculus teacher) about formulas and assumed "constants" like gravity and such.

I fail to see how it can be proved that these constants actually ARE constant ALL of the time. Is there someone in every spot on the planet constantly measuring the acceleration caused by gravity at sea level?

You need the values to be constant for the math to work, so they are. But in reality are they? Someone can prove beyond any doubt that throughout history (and thus any situation in which one of these formulas needs to be applied) and into the future that what we accept as constant values have been and will always be?

Then again we engineer a lot of crap based on these values and the stuff seems to work. So I dunno. It just doesn't make sense to me. There is a shitload of assuming going on.

Yes I am bored today. Heal shoulder, damn you!

[Kurlon]

The assumptions made in the electrical question would be implied by the fact that there are no units given for anything. It's kind of a basic premise of circuit analysis that switches and wires are zero resistance, and lamps are nonzero resistance. This is not the case, but it's necessary for solving those sort of problems. Sort of like assuming all beams are rigid for the purposes of solving a statics problem.

Fair enough. I've been playing on the practical side for too long and forget to switch to theoretical for stuff like this. D-oh! Still got an 80 so I'm happy.

[SSearchVT]

Add all the resistance you want, current will still flow through both paths. By playing with the resistance (or lack there of) all you're doing is altering the balance of the curent going through each path, but nothing short of infinate resistance is going to keep current from taking both routes.

Exactly - the third light may not be as bright as the other two - but it would still be lit. The writer of the question leaves out a ton of details (wire gauge, switch resistance, etc).

[ZX-12R]

Since everyone else is bitching about questions, I didn't like the one about one fan causing another to spin. Their correct answer is that they both spin in the same direction. I answered that they spin in opposite directions because for air to go from entering the rear and exiting the front of the fan to entering the front of the second and exiting the rear, it would have to spin in the opposite direction.

Why do they call it taking a dump when you don't actually take it anywhere? Funk dat!

[Kitt]

i got an 86% haha....i'm actually pretty proud of myself.

thats a really cool lil test, nice find!

you have to chill with the carbon copy of nesr on myspace bulletins.

[SSearchVT]

Gotta wonder with all the errors found on this test - How many people didn't get into the school because they answered the questions correctly, but their answers didn't match what the writer claims is correct?

[Kurlon]

my $2700.00 design-aid software tells me u make shit way too hard for yourself.

Buh, your $2700 softy app is still showing current through the short bypassed circuit, not much but it's registering!

I'll go back to my cave now and continue waiting for the usps man to arrive with my CDI.

[ZX-12R]

Buh, your $2700 softy app is still showing current through the short bypassed circuit, not much but it's registering!

All SPICE based circuit simulators have trouble with zero resistance so you have to type in a value like 1e-15 as a minimum. It did predict that the bulb doesn't light up though!

[RyanNicholson]

you have to chill with the carbon copy of nesr on myspace bulletins.

haha what....when i come across something cool i post when i'm bored.

theres like 5000ppl on my list that aren't on here


i'm a myspace whore haha, but w/e....i get a decent amount of business off it

[wylee]

Yeah I always get in arguments with my step mom (calculus teacher) about formulas and assumed "constants" like gravity and such.

I fail to see how it can be proved that these constants actually ARE constant ALL of the time. Is there someone in every spot on the planet constantly measuring the acceleration caused by gravity at sea level?

Haha...gravity cannot possibly be a constant, if it was there wouldn't be changing tides. Well, I guess in theory Earth's gravity itself is probably a constant but throw in the variables of the moon's position, the position of Earth in it's orbit around the sun, and actual gravitational pull is no longer a constant.

[Honclfibr]

An engineer and a mathematician are placed in a room, 20 feet from a beautiful naked woman. They are instructed that every minute they are permitted to move half the distance between themselves and the woman.

The mathematician, sensing the paradox, cries "This is madness! If we keep moving half the distance each time, we'll never reach her! It's a mathematical impossibility!"

The engineer smilies and replies "Well that may be, but I'm certain we'll get close enough for all practical purposes".

[wylee]

An engineer and a mathematician are placed in a room, 20 feet from a beautiful naked woman. They are instructed that every minute they are permitted to move half the distance between themselves and the woman.

The mathematician, sensing the paradox, cries "This is madness! If we keep moving half the distance each time, we'll never reach her! It's a mathematical impossibility!"

The engineer smilies and replies "Well that may be, but I'm certain we'll get close enough for all practical purposes".

So the engineer intends to cheat when he get close enough to be within his arbitrary tolerances.

[Jaynnus]

A mathematician and an engineer are placed in a room with a beautiful naked woman. The naked woman takes one look at each of them...and heads to the biker bar.

[Honclfibr]

I think it's pretty obvious she had to be knocked unconscious for the experiment to work. Geez.

[978chris]

Since everyone else is bitching about questions, I didn't like the one about one fan causing another to spin. Their correct answer is that they both spin in the same direction. I answered that they spin in opposite directions because for air to go from entering the rear and exiting the front of the fan to entering the front of the second and exiting the rear, it would have to spin in the opposite direction.

Why do they call it taking a dump when you don't actually take it anywhere? Funk dat!

I did the same thing.

Fucking trick questions.

Which side of the fan(s) am I standing on?

Do you mean spinning the same way when viewing both together as from behind one of the fans, or do you mean which direction is the spinning relative to each individual fan?

Someone kill me.

[978chris]

Haha...gravity cannot possibly be a constant, if it was there wouldn't be changing tides. Well, I guess in theory Earth's gravity itself is probably a constant but throw in the variables of the moon's position, the position of Earth in it's orbit around the sun, and actual gravitational pull is no longer a constant.

Yes I keep trying to explain this to her.

Gotta wonder with all the errors found on this test - How many people didn't get into the school because they answered the questions correctly, but their answers didn't match what the writer claims is correct?

You should send this thread in and ask.

And yes, fans, fucking fans....

[SVRACER01]

the answer for the worm gear is wrong too.

[OreoGaborio]

no it's not

[978chris]

no it's not

+1

[OreoGaborio]

I had one of the building engineers take this test.... he only had enough time to answer a few, but he got more than 1/2 of them wrong.

makes me scared.