Rates of pressure and volume change

AI Thread Summary
The discussion revolves around calculating the speed of water flowing out of a hose connected to a sealed tank with compressed air. Given the tank's height and the pressures at specific water heights, Bernoulli's Equation is suggested as a relevant approach for determining flow speed. The problem also hints at the relationship between pressure changes and water height, indicating that the flow will cease when the water level drops to a certain point. The ideal gas law may also play a role in understanding the pressure dynamics as the water level changes. Overall, the focus is on applying fluid dynamics principles to solve for water flow rates at varying heights.
coding_delight
Messages
3
Reaction score
0

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 I am stumped at how to approach this problem so please help...i strongly appreciate it...
 
Physics news on Phys.org
Have you had Bernoulli's Equation yet? The fact that the problem asks for the speed of water flow and gives you pressure differences leads me to suspect that they want you to apply that. (Otherwise we'll have to work this out from basic principles...)
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Energy of a water tank with compressed air
Replies
5
Views
1K
Atmospheric pressure and water pressure - Boyle's law
Replies
6
Views
790
Air pressure changes in a vessel as the vessel volume increases
Replies
8
Views
934
Pressure in fluids and Archimedes' principle
Replies
2
Views
1K
Pressure inside a sealed container
Replies
9
Views
2K
Question on pressure, volume and rates of change
Replies
2
Views
6K
What is the relationship between pressure and flow rate?
Replies
8
Views
4K
Trouble solving for end state of two control volumes in a rigid tank
Replies
12
Views
2K
A water-bottle demonstration of atmospheric pressure
Replies
6
Views
2K
Finding speed of water leaving a pressurized vessel
Replies
1
Views
9K

Hot Threads

Recent Insights

Back
Top