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Jim recently noticed that the fashion of hurling oneself out of a balloon from a great height, has returned...
--- The said projectile will accelerate to the speed of sound and beyond on the way down
--- In the absence of a parachute the said projectile will form a small but not indiscernible
dent in the surface of the earth
--- Repeated projectile bombarment will drill a hole
Now imagine if you will, a projectile of water, frozen at great height, lofted by said balloon that melts away after said impact...
The varmint
Renewable_20Nuclear_20Energy
... [madness, Mar 26 2008]
Barnes Wallis' Tallboy
http://en.wikipedia.org/wiki/Tallboy_bomb
The original ground penetration weapon. Much more effective than that silly bouncing bomb thing he came up with. [wagster, Mar 26 2008]
[link]
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--- Gradually, a small lake forms, cushioning the impact of further missiles. Rendering this inane effort moot. |
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So, wait long enough to let the water evaporate between impacts. |
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Even ignoring rubble from the sides falling back into the hole, it's going to be a veeeery sloooooow drill... |
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//said projectile will accelerate to the speed of sound and beyond on the way down//
Only in the upper atmosphere. The terminal velocity near the earth will be much less. |
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Jim is very patient (infact he is dead)... |
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You are not concerned with the vapour pressure of water at high altitude...? |
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... or the effects of air friction on said block of ice?
(or, in fact, a balloon that melts away - surely a bad idea?) |
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I agree with [ldischler], I only know of one object, actually a man, which dropped from a balloon and accelerated past the speed of sound, luckily for all of us water has a much lower terminal velocity. I think ice would melt from friction if it went to fast. |
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High-pressure water is already used to bore holes in things, the ground included, without the expense of huge high-altitude balloons. |
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On the subject of things dropped from great heights in order to make big holes in the ground, I read with some amusement an eye-witness account of the military dropping worn-out artillery barrells by the gross out the back of a C-130 flying at 10,000 feet over caves and bunkers in Afghanistan. It puts an entirely new spin on the notion of 'waste disposal.' |
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Mister --- terminal velocity is a function of shape (and density in so much as it relates to shape). The terminal velocity of a tonne of feathers is infact less than the terminal velocity of a tonne of ice... |
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And no I am not concerned with temperature changes due to friction... What is required is that the journey up takes longer than the journey down. |
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