> Subject: RE: Question on a Physics Exam
>
> > > 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.
> >
>
>
>
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