To make things interesting we give you some choices... 1) Solve
the first puzzle and you will find the tools necessary to retrieve
the cache... 2) Or opt to solve the second puzzle only and be
prepared to improvise when you reach the cache!
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First Puzzle
Fluids have some amazing qualities ~ But it is the relationship
between depth and pressure that I find most intriguing.
P = p.g.h
P - pressure in Pascals (N/m^2) ; p (rho) - density ; g -
gravitational constant (9.8 m/s^2) ; h - height in meters
(depth)
The most remarkable thing about the above expression is what it
does not include. The fluid pressure at a given depth does not
depend upon the total mass or total volume of the liquid, only the
depth! No matter what the shape of the body of fluid, pressure is
only dependent on the depth!
Imagine the sunken wreck of a model submarine lying 9.2m below
the surface in fresh water. You need to displace 5160 cubic
centimeters of water out of the balast tank in order to render the
sub weightless in water. To salvage the wreck you attach a long
flexible tube to the balast tank and pump down air some which
displaces water from the sub.
On the day of salvage the air temperature is 22 degrees Celsius
and the water 5 degrees less. This is fresh water so consider
density to be 1000. Atmospheric pressure is 101.3kPa (this is
101300Pa). All your mates have turned out to watch the
salvage...
All you need calculate is the volume of atmospheric air that
will need to be pumped down into the balast tank (air in tank will
be at water temperature) to displace an amount of water so as to
make the submarine weightless in the water (answer in cubic
centimeters will yield ABCD - round off to the nearest cubic
centimeter). Remember the volume of air will be less when it
reaches the sub as it will be under pressure. Volume of the tube is
negligible. The general gas law, a combined formula for the laws of
Boyle and Charles will be most useful... And remember pressure in
water is in addition to atmospheric pressure! I.E. Absolute
pressure = (p.g.h) + 101300
p - Pressure in pascals ; V - volume in m^3 ; T - Temperature in
degrees Kelvin
Here is an online degrees Celcius to Kelvin
converter.
To find the tools visit the following coordinates with puzzle in
mind:
S 34 00.(A-D)(B)(C+D)
E 18 27.(C)(A-C-D)(B-D)
These numbers look familiar? Yes the coords are correct! Look
for a hole in the side! Return the tools when done...
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Second Puzzle
The seals on the submarine are rated to safely handle a pressure
gradient (I.E. pressure above atmospheric pressure) of 2 Bar
(200kPa) - With this in mind what would be the safe operating floor
of the submarine? Answer rounded off to the nearest centimeter will
yield KLMN.
Remember: P = p.g.h
P - pressure in Pascals (N/m^2) ; p (rho) - density (in this
case density is 1000 ; g - gravitational constant (always 9.8
m/s^2) ; h - height in meters (depth - this is what you want to
calculate!)
S 34 00.(M+M)(10-N)(K+L+N)
E 18 27.(K+L)(M+K)(M+M)
This will take you to a concrete square near the cache site...
Stand on this square - water passing beneath your feet would meet a
larger body of water at the cache site. At the cache site you will
find a thick black pipe with one end in the water and the other
resting up on the bank - explore the upper opening of this
pipe...
If you have solved the first puzzle and have found the tools you
will have a good ideas as to what to do... If not, well, keep the
puzzle in mind and improvise! - Just don't pull on anything! There
is also a nice long pole on the roof of the nearby pump-house - use
this to place the cache out of arm's reach for the next geocachers!
:)
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