More old news...
-------- Original Message --------
Subject: Re: [Jchat] recognizing numbers
Date: Wed, 01 May 2013 15:17:07 -0400
From: Robert Bernecky <[email protected]>
To: [email protected]
There was another lovely physics question:
3. If you were given a very precise barometer and a stop-watch.
how would you measure the height of the aeronautical
building on campus? [This was, at the time, the tallest building
on campus.]
A few possible answers were:
a. Measure the barometric pressure at the base of the building
and the top of the building. From an estimate of the
gravitational attraction of the planet, and the density of air
at STP in smog-laden Pasadena, determine the gradient
of air density per meter of height, and then use the difference
in pressure to determine the altitude difference.
b. Take the barometer to the top of the building and throw it off
the building, using the stopwatch to measure t, the time it
takes to fall. Assume that g, the acceleration of gravity
on the earth's surface, is 9.8m/s/s. Then, from s= 1/2 g t^2,
compute s.
c. Find the building superintendent and offer to give him/her the
barometer, iff you are allowed to look at the architectural plans
for the building.
Bob
On 13-05-01 03:00 PM, Roger Hui wrote:
% 142857
7.00001e_6
1 % 7
0.142857
See, too low brow for a Cal Techie.
I am surprised that your physics final did not have the question, "how many
piano tuners are there in Chicago"? It is said that any physicist worth
his salt can give a pretty good estimate.
http://en.wikipedia.org/wiki/Fermi_problem . I think Fermi was also the
one who estimated the yield in the Trinity test by tossing up some pieces
of paper and observing how far they traveled. His estimate was pretty
close to the actual yield (within a factor of 2?).
On Wed, May 1, 2013 at 11:45 AM, Robert Bernecky
<[email protected]>wrote:
It is, indeed, cool!
I think I was introduced to it there in my first physics
final, which had a bunch of one-point questions, such as these
two, intended to encourage you to think in metric:
1. Assume the speed of light is 186,000 miles per second. Compute
the speed of light in furlongs per fortnight.
2. Assume the speed of light is 300,000 kilometers per second,
and that there are π×10^7 seconds in a year. Compute the
distance light travels in a year.*
I don't recognize the other integer.
Bob
* I don't recall if the answer "one light year" was acceptable or not!
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