blueovalz Posted February 10, 2005 Share Posted February 10, 2005 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. The student appealed on the grounds that his answer was indisputably correct, and that the university appoint an independent arbiter to decide the case. The arbiter judged that the answer was indeed correct, but 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 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=.5g x t squared, but bad luck for 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 the 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 Sq root (I/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 Niels Bohr, the only person from Denmark to win the Nobel Prize for Physics. Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted February 10, 2005 Share Posted February 10, 2005 !M! Quote Link to comment Share on other sites More sharing options...
2126 Posted February 10, 2005 Share Posted February 10, 2005 That was a great story Terry! I quess most people, like the original examiner, aren't quit sure what to do when they find themselves outside of the box!!! Quote Link to comment Share on other sites More sharing options...
Guest tony78_280z Posted February 10, 2005 Share Posted February 10, 2005 “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=.5g x t squared, but bad luck for the barometer.â€Personaly I like this one. I don't know what a barometer looks like, but I bet it looks alot different after getting these measurements. =) Quote Link to comment Share on other sites More sharing options...
blueovalz Posted February 11, 2005 Author Share Posted February 11, 2005 Back when this took place a barometer was a frame, approximately 1 meter tall (thus it could measure the pressure of air at sea level ~30" all the way down to a vacuum - 0 inches as the column of mercury moved up or down this amount in the glass tube), and consisted of an attached evacuated glass tube with a scale beside it, whose open end was placed in a pool of mercury. A rather cumbersome device. No wonder he felt dropping it would do justice! Quote Link to comment Share on other sites More sharing options...
Guest 240zJake Posted February 11, 2005 Share Posted February 11, 2005 "...but bad luck for the barometer.†Bad luck for the barometer or bad luck for the guy that gets hit by all the mercury contained within? Quote Link to comment Share on other sites More sharing options...
Dat260 Posted February 11, 2005 Share Posted February 11, 2005 So how would you measure any modern skyscraper with that particular barometer? What would be the formula? Ari Quote Link to comment Share on other sites More sharing options...
materchan Posted February 11, 2005 Share Posted February 11, 2005 p(final)=p(initial)e^-mgh/kT DUH! Quote Link to comment Share on other sites More sharing options...
VRJoe Posted February 12, 2005 Share Posted February 12, 2005 Now a days it would be "bad luck for the barometer and the HAZMAT crew that clears a 6 block area and begins a massive cleanup". - Joe Quote Link to comment Share on other sites More sharing options...
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