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### Re: Amusing answers to tests

Posted: Fri Mar 21, 2008 3:11 pm UTC
Poochy wrote:I was once asked the standard-issue physics question about estimating the height of a building using a barometer. Except this particular test asked for all the possible ways we could think of, with no penalty for incorrect answers. I can't remember all of the methods I put, but amongst my answers:

1. Measure the barometric pressure at the top and bottom of the building and calculate the difference in altitude.
2. Drop the barometer from the roof of the building, and measure how long it takes to hit the ground. Calculate the distance the barometer fell based on that measurement (d=(1/2)*a*t2+v0*t, a=9.8m/s2 v0=0)
3. Drop the barometer from the roof of the building, and measure the difference in time between when you see the barometer hit the ground and when you hear the resulting thud. Use this to calculate the distance the sound traveled.
4. Drop the barometer from the roof of the building. Repeat until it hits a random passerby on the ground. Look in the news for a story that says "a man was badly injured today after being hit in the head by a barometer thrown off the roof of a X-foot-tall building." X will be the height.
5. Wait for a natural disaster to wreck the building. Take the barometer and smash the rubble until there are no large pieces left. The height of the building is approximately 0.

6. Measure the shadow of the barometer. Measure the shadow of the building. Since you know the height of the barometer, use trig to find the height of the building.
7. Go to the building super. Offer him a barometer in exchange for the height of the building.
8. Go to the top of the building. Measure the period of the earth's rotation. Go to the bottom of the building. Measure it again. Use conservation of angular momentum to determine the height of the building.

### Re: Amusing answers to tests

Posted: Fri Mar 21, 2008 4:59 pm UTC
BlackSails wrote:8. Go to the top of the building. Measure the period of the earth's rotation. Go to the bottom of the building. Measure it again. Use conservation of angular momentum to determine the height of the building.
Are we given the mass of the barometer?

### Re: Amusing answers to tests

Posted: Fri Mar 21, 2008 9:07 pm UTC
oxoiron wrote:
BlackSails wrote:8. Go to the top of the building. Measure the period of the earth's rotation. Go to the bottom of the building. Measure it again. Use conservation of angular momentum to determine the height of the building.
Are we given the mass of the barometer?

You can determine that by measuring the gravitational attraction between you and the barometer.

### Re: Amusing answers to tests

Posted: Fri Mar 21, 2008 9:13 pm UTC
Nicely played.

### Re: Amusing answers to tests

Posted: Fri Mar 21, 2008 10:18 pm UTC
Drop the barometer off the top of the building. Run down the stairs, and examine the mess. From the size and shape of the splatter, you can estimate the size of the building.

While standing on the ground, drop the barometer from shoulder height and from waist height, and time how long it takes to fall each time, and calculate the acceleration of the barometer. Do the same thing while standing on top of the building. Calculate the difference in the accelerations of the barometer, and use the fact that both gravitational attraction and air pressure change as you go higher to determine the height of the building.

This one doesn't even require you to leave the roof of the building! Measure the air pressure when the barometer is on the top of the building, when it is an inch above the top of the building, when it is two inches above the top of the building, etc. Use the fact that the amount of gravity affects the reading of the barometer, that air pressure changes linearly with respect to height (I think), and that gravity follows an inverse square law respect to height, to determine the distance from the top of the building to the center of the Earth.

### Re: Amusing answers to tests

Posted: Sat Mar 22, 2008 12:03 am UTC
Measure the height of the Barometer, go to the building's stairwell, place it against the ground an mark it's top.
Then, hold it in position so that the bottom of the Barometer is level with the mark you just placed, and place another mark at the top, continue this process to the top of the building, counting the number of marks you make, then multiply that number by the height of the Barometer.

### Re: Amusing answers to tests

Posted: Sat Mar 22, 2008 1:45 am UTC
Hurl the barometer against the top of the building. Time how long it takes for the force to be felt at the bottom of the building. Multiply that by the speed of sound in the material making up the building.

### Re: Amusing answers to tests

Posted: Sat Mar 22, 2008 2:13 am UTC
Stand at the bottom of the Building, with a large Spring, or piece of Elastic.
Hang the barometer from the spring, and find it's mass. Use the reults from the extension of the Spring to find it's Spring constant.
Station someone at the top of the bulding, hang the barometer on the end of the spring, and extend it directly downwards, and release, measuring the extension every time, release, and check with your accomplice to see if it reached te top, repeat until it has reached the exact height of the building.

Find the distance travelled usng the Elastic Potential energy of the Spring, the mass of the barometer, the Kinetic energy used to reach the top of the building, the barometer's Mass, and the deceleration due to Gravity (9.8Ms-2)

### Re: Amusing answers to tests

Posted: Sat Mar 22, 2008 6:24 pm UTC
stand on the edge of the building and threaten to jump. when a mob assembles, tell them you won't jump if they give you a ruler each. then break the barometer, use the shards to poke holes in the rulers and then stick a glass piece though each hole to connect them. now snagle the whole thing from the building.

### Re: Amusing answers to tests

Posted: Sat Mar 22, 2008 7:56 pm UTC
Hold the barometer still for about a minute, then suddenly shake it. Measure the time the gravitational wave needed to reach the detector at the bottom of the building.

### Re: Amusing answers to tests

Posted: Sat Mar 22, 2008 11:13 pm UTC
Exchange the Barometer for a pair of Extremely accurate clocks,
Place one at the top of the building and one at the bottom, and leave them there for about 80 years, then come back, measure the difference in time from each clock, and find the height using General Relativity.

### Re: Amusing answers to tests

Posted: Sun Mar 23, 2008 3:34 am UTC
bcoblentz wrote:On last quarter's EM final I barely knew how to do any of the problems so I wrote a nonsense 60-point bonus question. Not sure if I got any points for it but I passed the class...

I also used the "comments" space on the course evaluation form to write about my professor standing up to murderous pirates after our schooner was boarded. I wish I would have kept it.

My solid state physics final today (because I don't care one whit for solid state physics, not even enough to make me do the homework or read the text ) included something of a sequel to the pirate story, in which the professor plants a GPS tracking device on one of the pirates and uses it to find their secret hideout. I only earnestly attempted two out of ten problems because they were the only ones that made any sense to me, and spent the next hour filling my exam booklet with other nonsense, including the following:

-a discussion of secret military bases on the moon and a clandestine space war against the ancient gold-crazed alien creators of humanity, complete with schematics of a typical moon base, a sophisticated power generator, and a starfighter

-an intermission, during which I urged the grader to have a snack

-a Fermat-style claim to have proven Goldbach's conjecture

-a brief description of Star Control II's Druuge race

-a bogus explanation of X-ray scattering in an amorphous solid involving bones, including a plot of bone density

The odds against my passing the course are--somewhat fittingly because astrophysics is the closest thing to my specialty--astronomical, but it was a lot of fun.

### Re: Amusing answers to tests

Posted: Sun Mar 23, 2008 7:29 am UTC
Maseiken wrote:Exchange the Barometer for a pair of Extremely accurate clocks,
Place one at the top of the building and one at the bottom, and leave them there for about 80 years, then come back, measure the difference in time from each clock, and find the height using the difference between Special Relativity and General Relativity.
fix'd

### Re: Amusing answers to tests

Posted: Sun Mar 23, 2008 7:55 am UTC
-Find Lyra Belacqua and give her the barometer and see if she has some way of reading it to determine the height of the building that you would have previously thought beyond your magical (or arcane/Dust-related, anyway) means. Or, alternatively, offer her the barometer itself if she will ask her alethiometer what the height of the building is.

### Re: Amusing answers to tests

Posted: Sun Mar 23, 2008 10:21 am UTC
Noughmad wrote:Hold the barometer still for about a minute, then suddenly shake it. Measure the time the gravitational wave needed to reach the detector at the bottom of the building.

But I thought the speed of gravity is not known? (There are experiments showing it to be C, but I thought we had to wait for some new satellite or other to test it for real)

### Re: Amusing answers to tests

Posted: Sun Mar 23, 2008 12:32 pm UTC
BlackSails wrote:
Noughmad wrote:Hold the barometer still for about a minute, then suddenly shake it. Measure the time the gravitational wave needed to reach the detector at the bottom of the building.

But I thought the speed of gravity is not known? (There are experiments showing it to be C, but I thought we had to wait for some new satellite or other to test it for real)
Well, it's "approximately" c (wiki says +/- 20%), but there's something wrong with relativity if it isn't exactly c.

So, you'll probably get the Nobel prize if you're the first one to notice the height is wrong

### Re: Amusing answers to tests

Posted: Sun Mar 23, 2008 2:52 pm UTC
Nimz wrote:
Maseiken wrote:Exchange the Barometer for a pair of Extremely accurate clocks,
Place one at the top of the building and one at the bottom, and leave them there for about 80 years, then come back, measure the difference in time from each clock, and find the height using the difference between Special Relativity and General Relativity.
fix'd

Thank you.
I guess reading Brief History of Time doesn't make you an instant Super-Genius... *sigh*

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 6:46 am UTC
Maseiken wrote:
Nimz wrote:
Maseiken wrote:Exchange the Barometer for a pair of Extremely accurate clocks,
Place one at the top of the building and one at the bottom, and leave them there for about 80 years, then come back, measure the difference in time from each clock, and find the height using the difference between Special Relativity and General Relativity.
fix'd

Thank you.
I guess reading Brief History of Time doesn't make you an instant Super-Genius... *sigh*

You're welcome. I prefer QED (Quantum Electrodynamics) over A Brief History of Time for instagenius genesis.
The only reason I caught that was because I took a class on General Relativity, and one of the homework problems was a simplified GPS problem, where to get the timing signal right, both SR and GR had to be used. The GR effect was about 3 times as strong, and in the opposite direction as the SR effect in that simplified problem. I have my final from that class, but I don't have any particularly amusing answers in it or I'd share.

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 6:57 am UTC
Depends on what you mean by GR, I suppose. I tend to think of SR as a special case of GR, so from my point of view, this is just two effects in GR. I really don't think your fixage makes sense. GR makes the "correct" predictions. It is just as accurate, if not more so, to say that you're using GR to calculate the height as it is to say that you're using the difference between SR and GR.

I normally wouldn't be this pedantic, but y'know. Do unto others as they have done unto others still, or something.

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 10:08 am UTC
My Dad once solved a physics question to three possible answers: 30cm, 3m and 30m. Based on the question saying 'of average human height', he choose 3m. He got a bonus mark for indirect logic and showing the question to be inaccurate.

Personally I'm too much of a teacher's pet (and rarely can't see what I should be doing) to have many amusing answers, but I do generally correct the multiple questions after answering them, to show them to be implausible/impossible. Can't remember any at the moment though. The best I have personally is from my physics trial exam. I got 2/3's of the way through the question about a helicopter's downforce to realise that it was only a toy helicopter, apparently I said sh*t!? quite loudly but don't remember doing so.

In my friend's philosophy exam (or maybe it was just a joke question from his teacher) there was a essay question (for half the exam) that went:

Topic D: Free Will and Determinacy
Essay Question: Is it possible for you to choose not to answer this question?

1) Complete another essay half-arsed and finish with "Thus I have proved the essay question in Topic D"
2) Write "This statement is false" and leave the marker to squirm

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 10:17 am UTC
I think I would leave that one empty. Maybe write "This space intentionally left blank" at the bottom with my initials.

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 10:34 am UTC
"Not anymore."

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 3:50 pm UTC
Write something that has nothing to do with the topic.

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 5:10 pm UTC
While all the barometer ideas are amusing, I'm tempted to split them out into Forum Games if people keep flooding this topic with them.

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 11:55 pm UTC
Luthen wrote:Topic D: Free Will and Determinacy
Essay Question: Is it possible for you to choose not to answer this question?

I would explain why it would be impossible for me to choose not to answer the question:
• Not answering the question and having that be an affirmative answer might get a decent mark, but would be a risky move.
• I'm risk averse, and don't want to leave that much of the test to chance.
• etc.
I would, however, explain why someone else, who is either much ballsier than I, or already thinks they are failing, could decide not to answer the question.

### Re: Amusing answers to tests

Posted: Mon Mar 24, 2008 11:59 pm UTC
skeptical scientist wrote:
Luthen wrote:Topic D: Free Will and Determinacy
Essay Question: Is it possible for you to choose not to answer this question?

I would explain why it would be impossible for me to choose not to answer the question:
• Not answering the question and having that be an affirmative answer might get a decent mark, but would be a risky move.
• I'm risk averse, and don't want to leave that much of the test to chance.
• etc.
I would, however, explain why someone else, who is either much ballsier than I, or already thinks they are failing, could decide not to answer the question.

It's not asking "Would you choose not to answer this question?". There's still a possibility for you to not answer the question, despite your reservations to choose otherwise.

### Re: Amusing answers to tests

Posted: Tue Mar 25, 2008 12:11 am UTC
Nope, I couldn't choose not to answer that question and still be me. If you were in my shoes, perhaps you could, but I could not if I were taking the class. (I could if I were auditing it.)

### Re: Amusing answers to tests

Posted: Tue Mar 25, 2008 12:38 am UTC
I don't really know if it counts as part of the answer but on a recent calc test I turned a graph with Reimann sums on it into a city being attacked by a dinosaur

### Re: Amusing answers to tests

Posted: Tue Mar 25, 2008 8:46 am UTC
Column 8 wrote:"Asked to discuss the obligation to provide 'vacant possession'," writes Edward Loong, of Milsons Point, "the law student whose conveyancing exam paper I've just marked answered 'the vendor is also required to remove all alive and dead bodies prior to completion'." A bonus mark was awarded for this helpful reminder.

Ah, good old Column 8. Never lets me down.

### Re: Amusing answers to tests

Posted: Tue Mar 25, 2008 12:32 pm UTC
I'm not looking terribly forward to getting back the coursework that concluded with this: "I do not believe that there is general method for determining how large the samples of a population with a given distribution (and no other data) need to be so that their distribution appears to be normal, on that note I am probably mistaken."
gmalivuk wrote:While all the barometer ideas are amusing, I'm tempted to split them out into Forum Games if people keep flooding this topic with them.
Please do that, it'll make me ever so happy.

### Re: Amusing answers to tests

Posted: Tue Mar 25, 2008 3:15 pm UTC
the tree wrote:I'm not looking terribly forward to getting back the coursework that concluded with this: "I do not believe that there is general method for determining how large the samples of a population with a given distribution (and no other data) need to be so that their distribution appears to be normal, on that note I am probably mistaken."

Usually the answer is "about 50". Friendlier distributions (like the uniform dist.) need less, weirder distributions need more. Obviously, the upper end is unbounded.

### Re: Amusing answers to tests

Posted: Tue Mar 25, 2008 4:39 pm UTC
In my last French test, the final task was to write a letter the protagonist of the book we were reading could have written to his parents when he arrived at his new school. However, the teacher made a huge mistake. He put the task up like this: (Translated)

3. Imagine a letter Grégoire could have written to his parents after his first day at his new school.

My first answer was the following:

Done!
And now?
What?
No, I'm sure! The task didn't say anything about writing that letter.

But I did not have the balls to leave it as an answer because my french grade is quite important to me. Narf! Anyway I'm still looking forward to the teacher's comment.

### Re: Amusing answers to tests

Posted: Fri Apr 04, 2008 3:20 am UTC
Luthen wrote:d's philosophy exam (or maybe it was just a joke question from his teacher) there was a essay question (for half the exam) that went:

Topic D: Free Will and Determinacy
Essay Question: Is it possible for you to choose not to answer this question?

1) Complete another essay half-arsed and finish with "Thus I have proved the essay question in Topic D"
2) Write "This statement is false" and leave the marker to squirm

i would of turned the whole test in blank, when asked why "if i answered any questions i would of compromised the integrity of topic d."

### Re: Amusing answers to tests

Posted: Fri Apr 04, 2008 7:18 am UTC
This isn't exactly an amusing answer, but I did do this once in my astronomy class my freshman year.

I showed up late to a quiz and rushed through the entire thing trying to finish it before he called time. He called time and I had not QUITE finished. He told everyone to stop writing and turn our quizzes in then we could go. Everyone got up, but I was still there furiously writing. When I had finally finished, I ran to the front table and was the last one to turn my quiz in. The teacher looked at me and said, "I can't take that. You didn't finish in time." I hadn't exactly had the best day so far, so I looked him straight in the eye and said "Do you have any idea who I am?!" The teacher looked smugly back at me and since it was a big class and it was early in the semester he said "No, as a matter of fact I don't." I picked up half the quizzes, put mine in the middle, put them back together, and tapped them on the desk a couple times to straighten them in a nice, neat pile. I looked up at him and said "Good." He grinned, nodded his approval and I walked out.

### Re: Amusing answers to e-mails XD

Posted: Fri Apr 04, 2008 7:46 am UTC
halfhearted attempt to razz a newbie

Instead of that, I'll share an e-mail I just got from a professor for one of my classes this quarter. The class was full before I registerred, so I need him to add me. I've changed the teacher's name here to Teacher Name to respect his privacy.
Hi Nimz,

T. Name

----- Original Message -----
From: Nimz O'Vich <e-mail@ddress>
Date: Thursday, April 3, 2008 9:14 pm
To: teacher@university

Hello Dr. Name.

I came to your office last night to add Math 610, but I wasn't sure what my student ID number was. It is <SIDN>, and my name is Nimz O'Vich. Thank you again for letting me add the class.

Sincerely,
Nimz
A few minutes later he sent the following:
Sorry, I misspelled.

T.N.
It was amusing to think that I'd be advertised tomorrow
And that student ID number thing has haunted me before. See the confession thread (page 486).

 500th post. How about that.

### Re: Amusing answers to tests

Posted: Fri Apr 04, 2008 7:48 am UTC
Twip wrote:This isn't exactly an amusing answer, but I did do this once in my astronomy class my freshman year.

I showed up late to a quiz and rushed through the entire thing trying to finish it before he called time. He called time and I had not QUITE finished. He told everyone to stop writing and turn our quizzes in then we could go. Everyone got up, but I was still there furiously writing. When I had finally finished, I ran to the front table and was the last one to turn my quiz in. The teacher looked at me and said, "I can't take that. You didn't finish in time." I hadn't exactly had the best day so far, so I looked him straight in the eye and said "Do you have any idea who I am?!" The teacher looked smugly back at me and since it was a big class and it was early in the semester he said "No, as a matter of fact I don't." I picked up half the quizzes, put mine in the middle, put them back together, and tapped them on the desk a couple times to straighten them in a nice, neat pile. I looked up at him and said "Good." He grinned, nodded his approval and I walked out.

That's definitely an urban legend. And why would he smile?

### Re: Amusing answers to tests

Posted: Fri Apr 04, 2008 7:52 am UTC
Sour Apple wrote:
Twip wrote:This isn't exactly an amusing answer, but I did do this once in my astronomy class my freshman year.

I showed up late to a quiz and rushed through the entire thing trying to finish it before he called time. He called time and I had not QUITE finished. He told everyone to stop writing and turn our quizzes in then we could go. Everyone got up, but I was still there furiously writing. When I had finally finished, I ran to the front table and was the last one to turn my quiz in. The teacher looked at me and said, "I can't take that. You didn't finish in time." I hadn't exactly had the best day so far, so I looked him straight in the eye and said "Do you have any idea who I am?!" The teacher looked smugly back at me and since it was a big class and it was early in the semester he said "No, as a matter of fact I don't." I picked up half the quizzes, put mine in the middle, put them back together, and tapped them on the desk a couple times to straighten them in a nice, neat pile. I looked up at him and said "Good." He grinned, nodded his approval and I walked out.

That's definitely an urban legend. And why would he smile?

That's where I got the idea. It was pretty much the only thing I could think of to do at the time. I got lucky and got a professor with a sense of humor.

### Re: Amusing answers to tests

Posted: Fri Apr 04, 2008 7:59 am UTC
That's wonderful. My college is too small to do that.

### Re: Amusing answers to tests

Posted: Fri Apr 04, 2008 12:30 pm UTC
notzeb wrote:This one doesn't even require you to leave the roof of the building! Measure the air pressure when the barometer is on the top of the building, when it is an inch above the top of the building, when it is two inches above the top of the building, etc. Use the fact that the amount of gravity affects the reading of the barometer, that air pressure changes linearly with respect to height (I think), and that gravity follows an inverse square law respect to height, to determine the distance from the top of the building to the center of the Earth.

pressure doesn't decrease linearly with altitude. pressure is force per unit area, or acceleration*mass per unit area, the acceleration is decreasing with r2 and the mass of air above a unit area also decreases faster than linearly as the density of lower pressure air is less. this doesn't stop you from using that method however, it just means you have more complex integrals for your pressures that you need to solve for height.

### Re: Amusing answers to tests

Posted: Fri Apr 04, 2008 4:24 pm UTC
Yes. Any hypothesis about pressure that leads to the conclusion that if you go high enough, the pressure is negative is probably false.

If you assume the atmosphere is stable, then the pressure above and below a bit of air of thickness dh should differ by exactly the right amount to counteract the gravitational force per unit area acting on that bit of air, which is either -p*g*dh (if you're close enough to the surface that g is constant) or -p*G*mE*dh/h2 if you are not. So close to the surface of the Earth, pressure does decrease approximately linearly, since the integral of p*g*dh is linear in h, but over larger intervals, if the density of air is approximately constant, you get P(h) = ∫-p*G*mE*dh/h2 = p*G*mE/h. (The constant of integration is zero since we expect that atmospheric pressure should tend to zero as we get further and further into outer space. If we lived in fluidic space, it would be nonzero.)

In truth the density of air is not constant, but depends on both pressure and temperature, so the true function is more complicated still, and do solve it you need to know how temperature varies with elevation.