On 2010/10/22, at 05:10 , Michael Payne wrote:
The collapsed Hanger at Dulles Airport, Length 100 x 50 m. Snow
weighs 10% of rain. If we have 80 cm of snow, it's 8 mm of rain. 1
millimeter of rain is 1 liter per square meter or 1 kg per square
meter. Therefore the roof area of that hanger is 100x50=5000 m2
times 8 kg/m2 = 40,000 kg or 40 metric Tons (Tonnes) additional
load. I did not need a calculator.
Dear Michael,
I couldn't help myself.
Here is your calculation done in Roman numerals:
The Dallas hangar is approximately CD Roman feet by CC Roman feet. The
snow that fell was •••• Roman feet so the volume of snow is obviously
CD x CC x •••• and, given that the density of water in Rome is about
XLV libra per cubic Roman foot, the mass of this snow is clearly CD x
CC x •••• x XLX and the overall mass of the snow on the roof is (CD x
CC x •••• x XLX) ÷ MM Roman tons (if they existed). I used Wikipedia
as the reference for these figures and I will leave the final
calculation for your amusement; I would appreciate it if you kept
track of the time it took you to complete this calculation and let me
know.
Here is your calculation done in customary measures:
The Dallas hangar is approximately 325 feet by 160 feet. The snow that
fell was 1/3 of an inch or 1/36 of a foot so the volume of snow is
obviously 325 x 160 x 1/36 and, given that the customary density of
water is about 62 1/2 pounds per cubic foot, the mass of this snow is
clearly 325 x 160 x 1/36 x 62 1/2 and the overall mass of the snow on
the roof is (325 x 160 x 1/36 x 62 1/2) ÷ 2000 short tons. I used
Wikipedia as the reference for these figures and I will leave the
final calculation for your amusement; I would appreciate it if you
kept track of the time it took you to complete this calculation and
let me know.
And here is my statement of the problem using metric system units:
The Dallas hangar is approximately 100 metres by 50 metres. The snow
that fell was 80 centimetres, which is the equivalent of 8 millimetres
of rain so the volume of water is obviously 100 x 50 x 8 litres and,
given that the density of water is exactly 1 kilogram per litre, the
mass of this snow is clearly 100 x 50 x 8 x 1 and the overall mass of
the snow on the roof is (100 x 50 x 8 x 1) ÷ 1000 = 40 tonnes. I
didn't need to use Wikipedia or any other reference for these figures
and, like you, I did the calculations in my head (but then checked
them with a calculator). Time taken for calculation: less than 5
seconds for mental arithmetic and 10 seconds for calculator checking.
Cheers,
Pat Naughtin
Author of the ebook, Metrication Leaders Guide, see
http://metricationmatters.com/MetricationLeadersGuideInfo.html
Hear Pat speak at: http://www.youtube.com/watch?v=_lshRAPvPZY
PO Box 305 Belmont 3216,
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Phone: 61 3 5241 2008
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