Question on pressure, volume and rates of change

  • #1

Homework Statement


A large tank of water has a hose conected to. The tank (a cylinder) is 4.0 m in height and the tank is sealed at the top and has compressed air between the water surface and the top. When the water height h has the value 3.50m, the absolute pressure p of the compressed air is 4.20*10^5Pa. Assume that the air above the water expands at constant temp. and take the atmospheric pressure to be 1.00*10^5Pa. What is the speed at which the water flows out of the hose at h = 3.0m and h = 2.0m? at what value h does the water stop flowing?


Homework Equations



I'm pretty sure this involves the ideal gas equation of state PV = nrT and maybe the fact that the volume increase or decrease dV with respect to time is equal to the height increase or decrease dh with respect to time....

The Attempt at a Solution



I have tried quite a few things but to be honest im stumped at how to approach this problem so please help...i strongly appreciate it...

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2

Homework Statement


A large tank of water has a hose conected to. The tank (a cylinder) is 4.0 m in height and the tank is sealed at the top and has compressed air between the water surface and the top. When the water height h has the value 3.50m, the absolute pressure p of the compressed air is 4.20*10^5Pa. Assume that the air above the water expands at constant temp. and take the atmospheric pressure to be 1.00*10^5Pa. What is the speed at which the water flows out of the hose at h = 3.0m and h = 2.0m? at what value h does the water stop flowing?


Homework Equations



I'm pretty sure this involves the ideal gas equation of state PV = nrT and maybe the fact that the volume increase or decrease dV with respect to time is equal to the height increase or decrease dh with respect to time....

The Attempt at a Solution



I have tried quite a few things but to be honest im stumped at how to approach this problem so please help...i strongly appreciate it...

Homework Statement



to find a solution on question 1 is just a ratio and proportion between pressure and height h@3m/p@3m=h@3.5m/P@3.5m, when you get the pressure apply it to the bernoulli's principle or equation then you obtain the velocity because you have a very big tank the initial velocity is zero and your output pressure is zero because it is discharges to the atmosphere "assuming".


2. Homework Equations [/b

this is not an ideal gas because we are talking about water in this problem



The Attempt at a Solution



to obtain the height at when it stop flowing your pressure at that particular height must be atmospheric, apply ratio and poportion approach
 
Last edited:
  • #3
to obtain the height at when it stop flowing your pressure at that particular height must be atmospheric, apply ratio and poportion approach
,used the same equation you used in the first question
 

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