Mondays Musings

[Kip Powick]

The following concerns a question in a physics degree exam at the University of Copenhagen:

"Describe how to determine the height of a skyscraper with a barometer."

One student replied: "You tie a long piece of string to the neck of the barometer, then lower the barometer from the roof of the skyscraper to the ground. The length of the string plus the length of the barometer will equal the height of the building."

This highly original answer so incensed the examiner that the student was failed immediately. He appealed on the grounds that his answer was indisputably correct, and the university appointed an independent arbiter to decide the case. The arbiter judged that the answer was indeed correct, but did not display any noticeable knowledge of physics.

To resolve the problem, it was decided to call the student in and allow him six minutes in which to provide a verbal answer which showed at least a minimal familiarity with the basic principles of physics. For five minutes the student sat in silence, forehead creased in thought. The arbiter reminded him that time was running out, to which the student replied that he had several extremely relevant answers, but couldn't make up his mind which to use.

On being advised to hurry up the student replied as follows:

"Firstly, you could take the barometer up to the roof of the skyscraper, drop it over the edge, and measure the time it takes to reach the ground. The height of the building can then be worked out from the formula H =0.5g x t squared. But bad luck on the barometer."

"Or if the sun is shining you could measure the height of the barometer, then set it on end and measure the length of its shadow. Then you measure the length of the skyscraper's shadow, and thereafter it is a simple matter of proportional arithmetic to work out the height of the skyscraper."

"But if you wanted to be highly scientific about it, you could tie a short piece of string to the barometer and swing it like a pendulum, first at ground level and then on the roof of the skyscraper. The height is worked out by the difference in the gravitational restoring force T = 2 pi square root (l / g)."

"Or if the skyscraper has an outside emergency staircase, it would be easier to walk up it and mark off the height of the skyscraper in barometer lengths, then add them up."

"If you merely wanted to be boring and orthodox about it, of course, you could use the barometer to measure the air pressure on the roof of the skyscraper and on the ground, and convert the difference in millibars into feet to give the height of the building."

But since we are constantly being exhorted to exercise independence of mind and apply scientific methods, undoubtedly the best way would be to knock on the janitor's door and say to him 'If you would like a nice new barometer, I will give you this one if you tell me the height of this skyscraper'."

The student was Nils Bohr, the only Dane to win the Nobel prize for Physics.

[Trader]

THAT, I like.

I had this question asked of me during an interview. Had nothing to do withteh job and it was the only non personal question asked. Its purpose, I was told later, was to see how I thought and reasoned:

"Why is a manhole cover round?"

[Super 80]

I did that on a few economics exams, I usually got atleast part marks if the answer made some sort of sense. Which was more than I would have got if I tried to answer the question properly.

Ahh, university economics without high school math, almost as fun as drowning in a septic tank, but without the feeling of optimism.

No idea how I passed, but they can't take it away from me now.

[Kip Powick]

"Why is a manhole cover round?"

The only thing I can think of is that because of its weight it would be easier to handle by one man, and I'd guess that it is made round so that it can't fall in the manhole.

I give up...what is the correct answer??

[Guest Starman]

When I was very young, my Dad used to tell me that the shape of the pyramids was due to the Camel's triangular anus. And I once had a Physics teacher tell me, "When measuring the depth of a pit toilet by sound, don't forget to take into account the distance from your a-hole to your ears."

No wonder I grew up with a fondness for Monty Python sketches...

A manhole cover is round because basically it is a cap at the end of a vertical culvert. The concrete tube below ground is cylindrical for maximum strength against the pressure of the earth around it.

[Trader]

Both good answers. I was told that the cover is round so that it can't fall in the hole---good one Kip!!!!

I, of course, got it wrong!