Water pressure in a tank problem

AI Thread Summary
To determine the minimum pressure of water at the bottom of a 15-meter water tower, the equation P = pgh is used, where p is the density of water, g is the acceleration due to gravity, and h is the height. The initial calculation of 147150 pascals or 1.45 atmospheres was correct, but it failed to account for atmospheric pressure, which adds approximately 100,000 pascals. Including atmospheric pressure results in a total pressure of around 247150 pascals or 2.47 atmospheres. The discussion highlights the importance of considering both water and air pressure in such calculations. Ultimately, the correct answer requires factoring in atmospheric pressure for accuracy.
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Homework Statement



A water pipe feeds a water tower with water. The tower is 15 metres tall.
If the water is to flow into the tank what is the minimum pressure of water at the bottom of the tower?
Assume litre of water = 1 kg
Assume 1 BAR = 1kg cm-2

Homework Equations



P = p g h ?

The Attempt at a Solution



am i using the correct equation...?
 
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1000 * 9.81 * 15 = 147150 or 1.45 atmopspheres? :rolleyes:
 
It doesn't matter if you use pascals or atmospheres. And the formula is correct.
 
pinsky said:
It doesn't matter if you use pascals or atmospheres. And the formula is correct.

ah okay, thanks. Is the answer correct?
 
Either you didn't express yourself good enough or you're asking a stupid question. :)
 
hah :redface:
 
turns out i got this WRONG! any thoughts?!
 
Apparently You had to count in air pressure (10^5 pascals) since it can still exert pressure on the bottom...Is it correct with that added?
 
lolrelativity said:
Apparently You had to count in air pressure (10^5 pascals) since it can still exert pressure on the bottom...Is it correct with that added?

Yeah you're right, i didn't factor in surface pressure. doh!
 
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