What is the difference in pressure in the portions of the pipe before and after the rise?
372621
Since the speed is constant, the pressure difference is only due to the pressure exerted by the 4m column of liquid.\n\nThe pressure exerted by “h” column of liquid of density‘d’ is hdg.  (g= 9.81 m/s^2). \n\nhdg = 4 x 925 x 9.81 = 36297 pascal.
347099
I have used the Bernoulli equation to calculate pressure drop through piping and to size pumps (determine required head pressure).  You can't get much more real than that.
1063906
You're confusing resistance with pressure. If indeed there is a difference in voltage between A and B then there will be flow.\nThink of a tank filled with water held a few feet above another tank that has a pipe joining the two. Water will flow to the lower container thru the pipe. In this case the pipe has no resistance, which means water flows at maximum possible speed.\nIf both tanks are at the same level, then, sure, there will be no water flow. That's not how the problem was stated, however.
786817
Anywhere there is a difference in pressure. Examples:\nLow pressure in a vaccum cleaner, higher pressure outside pushes the air into the cleaner. Different pressure in a house compared to outside, when you open a window the higher pressure flows to the lower pressure. Remember that it is always a push and never a suck. Science never sucks!
966798
I may get confused on this. Increasing diameter lowers the pressure, but, increases volume. In a house we normally use a large pipe as a main and it supplies volume. Then we decrease pipe size to various Faucets and Water Heaters depending on their input size. When done properly you can flush a toilet without the shower burning someone. A sink Faucet will have more pressure from less diameter, but, it will have less volume. So, a sink faucet may fill a gallon jug slower than the Garden Hose Faucet. I hope I explained this correct. Been a while I worked with this stuff.\nYea, what is said above more correct, I give them a Thumbs Up. Velocity what I was trying to think of. Like a spray nozzle on a Garden Hose. The velocity make it seem it more pressure.
634368
Low pressure develops when pockets of warm air rise.\n\nHigh pressure develops when air sinks. It is literally pushing down.\n\nAir pressure in general changes due to elevation. The higher up you go, the less air. In turn, there is less air pressure. This is due to the forces of gravity.
1168897
It depends on the pressure pump and the resistance of the pipe.\nSee http://docs.bentley.com/en/HMFlowMaster/FlowMasterHelp-06-02.html
437723
Pressure increases as altitude increases. Also, underwater, when elevation decreases.
412802
p=F/A \n\nSo, you have the pressure of the atmosphere pluss the weight of the water above you.  Which is usually figured as a cylinder.  Hope that helps.
1078399
i'm not very sure if this is what you're looking for, but for a closed system with constant temperature, pV=p'V'. since volume, V = pi x (diameter/2)^2 x length, with constant length of the pipe, we have V = k(diameter)^2, where k is constant. hence, pV=p'V' is rewritten as p(diameter)^2 = p'(diameter')^2, i.e. p'/p =(80/250)^2. the new pressure is 0.1024 the original pressure.
360345
The water supply was at a higher elevation than the fountain, which created pressure. It's the same principle as community water towers of today.
1043213
That may depend on your application.  The pressure drop will depend on whether you are filtering gas or liquid and whether you are interested in the pressure drop of new filter samples or filters in use as they become clogged.  Flow rate will also increase pressure drop.\n\n\nFor example, if the filter is installed at as joint in a round horizontal pipe, and the flow is liquid (water?), and the pressure is relatively low, you can attach vertical plastic tubes with pipe fittings upstream and downstream of the filter.  If the water rises say one foot higher in the upstream tube than the downstream tube, the pressure drop across the filter is 12 inches w.g. (water gage).  If the pressure is too high for plastic tubes (where about 15 psi would require 34 foot high tubes), you can attach pressure gages to the pipe fittings and compare their readings or install a differential pressure gage across the fittings to directly read the pressure drop.\n\nIf the flow is a gas (air?), flowing through a duct, you can install a clear plastic "U" tube partially filled with water (and food coloring?) across fittings upstream and downstream of the filter to measure the pressure drop in inches w.g. or use a sensitive differential pressure gage.  Hope that helps a little.
601836
1)typical atmospheric pressure is 1atmosphere or 10^2kilopascals or 760mmHg.\n2)Atmospheric pressure decreases with altitude.So external pressure decreases.As preessure decreases volume increases(if the temperature change is insignificant)\n3)Water pressure increases with depth (P=h*density*g).So as external pressure increases the volumme decreases.\n4)Here we assume that the temperature doesn't change in the process.Use Boyle's law PV=P'V'\nso 760*V=1.30*0.21\nwhich gives V=3.59*10^-4L
978221
p = 136(1 - e^(-0.51t))\n\n(i) Find the initial value of the pressure\n\nInitial always means at t = 0\nWhen t = 0,\np = 136(1 - e^(-0.51*0))\n= 136(1 - e^(0))\n= 136(1 - 1)\n= 0 bars\n\n(ii) Find the value of the pressure after 2.39 minutes\n\nWhen t = 2.39\np = 136(1 - e^(-0.51*2.39))\n= 136(1 - e^(-0.51*2.39))\n= 136(1 - e^(-1.2189))\n≈ 136(1 - 0.295555)\n≈ 95.80 bars\n\n(iii) Find the value of the pressure once it has settled after a long period of time\n\nAs t gets large  e^(-0.51t) = 1/e^(0.51t) = 1/(large nimber) and so gets smaller and smaller.\nTherefore (1- e^(-0.51t) gets closer and closer to 1\nSo p=136(1- e^(-0.51t))\ngets loser and closer to 136 * 1\nie it will settle on p = 136 bar\n\neg when t = 30 minutes (½ hour)\n\np = 136(1 - e^(-0.51*30))\n= 136(1 - e^(-15.3))\n≈ 136(1 - 2.266 x 10^(-7))\n≈ 136
107278
the pressure rises.  this is because the molecules move faster.  if you want a formula use PV=nRT.  solve for P to get  P = (nRT)/V .\n\nsince the can is sealed, Volume stays the same.  R is a constant value anyway, n is the number of moles, which stays the same.  if you increase T, then P has to increase as well
31492
the answer to your question is pretty simple in logic.\nthe factor K for venturimeter is higher since the friction due to obstruction to the flow is higher in the case orificemeter. where as in the case of venturimeter the friction due to the difference in flow area is compensated by graduated tapering.
431380
If the pressure is 0.76m of Hg, it is equivalent to 10.3 m of water. There is a vacuum in the tube above this water height.\n\nHowever, by “vacuum” we mean inside this space, the pressure is low. There will be vapour of water which will have some pressure.\n\nEven in mercury barometer, there will be mercury vapour inside the “Torricelli’s vacuum”.  \n\nThis is the reason that ordinary pump which sucks water from a well or sump is not able to lift water to a height more than 10m from the surface of the water.