Water Definition and 1000 Threads

  1. H

    Resultant force from water on dam

    Homework Statement : [/B] The cross-sectional profile of a dam is shaped as an isosceles triangle. The dam is standing on horizontal ground and the watermirror is as high as the top of the dam. The dam has height h, length l and the distance from the bottom to the watermirror along the dam's...
  2. S

    Hydrostatics: Immersing a metal cube in water......

    Homework Statement A metal cube is placed in an empty vessel. When water is filled in the vessel so that the cube is completely immersed in the water,the force on the bottom of the vessel in contact with the cube (A) will increase (B)will decrease (C)will remain same (D) will become zero...
  3. Gabriele99

    Will water flow ever stop if we increase resistance?

    Complete question: Will flow ever reverse or stop if we increase resistance in this pipe scenario? There are 2 comunicating vessels. The highest vessel is coninuosly alimented with new water. Water in excess flows down on the sides. Water will try to reach the same height in both vessels, so...
  4. G

    Water tower: Why is all the water at the top?

    Hi. Most water towers store their water in a huge container at their top. Why? Wouldn't it be easier to place the container at the bottom and just add a long, thin pipe upwards to create the hydrostatic pressure? Is the problem that the container would need to endure too much pressure? Or that...
  5. AlaskaJoe73

    Design load of a water tube ride, such as on a cruise ship

    When designing the structure of an elevated water tube ride (water flows by gravity through a tube large enough to accommodate 2 people on a float, say 500 lb. max. and the volume of water is constant) how much effect does the object floating on the water have?
  6. Bikash Kumar Das

    I Relative Permitivity, Permeability & Refractive Index of Water

    How does the relative permitivity and relative permeability related to the refractive index of a dielectic medium like water?
  7. R

    Chemical terminology for an electron in water

    I've read several papers that talk about electrons in water, clearly they don't last very long as they react quickly with the oxygen. But I'm confused about the terminology they use, some call them solvated electrons, some hydrated electrons and others aquated electrons. I can't seem to find a...
  8. N

    If you threw a warm water balloon into space, would it boil?

    And by how much would the balloon expand, if at all?
  9. S

    Sanity check on falling steel ball in water

    Homework Statement What is the speed of a 5 mm steel ball falling through water at 10 C[/B] Viscosity of water: 1.3059 * 10-3 Pa*s (Various online sources) Homework Equations Laminar flow: Vt = gd2 (ρp - ρm)/18μ Vt = terminal velocity g = gravity (10m/s2) d = diameter of ball ρp =...
  10. K

    Calculating Velocity of Water Flow in Open Channel

    Homework Statement [/B] We have water flowing in an open channel. A small tube is placed in the channel, and the water raises to a height "l" above the water surface. The distance from the water surface to point 1/2 (points are at same height) is d. At point 1 the fluid velocity is V1 and at...
  11. J

    Pressure in the vessel containing water

    Homework Statement Homework EquationsThe Attempt at a Solution I think the pressure that the question is relating is the vapour pressure but I do not understand how that depends on the volume of the water contained in the vessel .Is there a relationship between the two ?
  12. J

    How does the density of water affect a sphere dipped in it?

    Homework Statement Homework EquationsThe Attempt at a Solution There can be two cases 1) The sphere might be a shell such that it floats on the water .When the temperature increases , even though density of water decreases , the force of buoyancy should remain same . Because force of...
  13. K

    Pressure on a vertical rectangular plate submerged in water

    The question goes as follows..: A car driver has an accident and drives into a lake. The car sinks to the bottom. The distance from the car door to the water surface is 10m. The car door is 0.9m wide and 1.3m tall. Assume that the car door can be approximated as a vertical rectangular plate and...
  14. NCBryan

    How can 10% ethonal gas produce 73% alcohol? (with water)

    I purchased 22.752 gallons of gasoline containing +- 10% ethanol dispensing it into a 23 gallon gas tank. Then I drove 23 miles (mostly up hill) to a job site. At lunch time I was not able to crank the engine. The symptoms were clear, it was water in the gas. I have a video if you want to see...
  15. G

    Pressure of 11,000m Water Column: Crushing or Equal to Bottom of Ocean?

    Suppose a cylinder was made. It is the same height as the deepest part of the ocean to the ocean surface - about 11,000 metres and about 1 metre wide. The cylinder was filled with water right to the top and stood on the Earth's surface. A small hole at the bottom of the cyclinder was opened...
  16. F

    Stagnation point and a water dam

    Hello Forum, I am clear on what the pressure at a point ##P## is on the wall of heigh of a dam at a certain depth ##d## below the water free surface: ## \rho g d+P_atm##. The deeper we go the higher the pressure. Now let's consider a different scenario: there is initially no water and water...
  17. J

    Thermodynamics: Dropping a hot horseshoe into a pot of water

    Homework Statement A freshly-forged iron horseshoe, with a mass of 0.549 kg is dropped into a 0.281 kg iron pot which contains 1.60 kg of water at 21.4 oC. After the horseshoe, pot and water reach thermal equilibrium they have a temperature of 29.8 oC. Assuming the pot and the water were in...
  18. A

    Surface Tension of needle on water

    I attempted the question but it was wrong... I don't understand where i went wrong my working seems logical, can someone please help. When a needle is gently placed on the surface of still water (γ = 0.0730 N.m-1) it can be supported by surface tension if the mass of the needle is small enough...
  19. C

    Pumping water upwards in a column

    Homework Statement Suppose you have a tank 10 m high. The tank is currently filled 5 m high with 1000 kg of water. How much energy does it take to pump in another 1000 kg of water from the bottom to fill the column to 10 m? (Ignore friction, etc.) Homework Equations E = m*g*h The Attempt at...
  20. T

    Would this work? (air filled tube inside a water filled container)

    Hey, I am from Turkiye, 17 yo and studying at high school. I have a project and would be better to know whether or not my project will work. I tried to draw it simply on paint and will tell you about some important points of it. Image 1 is the main body, its something solid and waterproof. It...
  21. T

    Head Calculation of a hot water circulating pump

    Hello, I have the following hot water system. I have a water heater with a pressurized cold water inlet. A re circulation line is taken near the farthest fixture passed through a circulating pump and back to the heater inlet. When calculating pump head, do I calculate pressure drop in the entire...
  22. J

    Freezing of water inside a hollow sphere which is rolling

    Homework Statement If we have a hollow ball completely filled with water which is rolling without slipping on a horizontal ground. If the water freezes which of the parameter will remain unchanged- angular speed, angular momentum, linear momentum, kinetic energy, total energy Homework...
  23. T

    I Explaining the size of a water molecule

    I am a longtime producer and host of a children's radio show on our local public radio station. It's springtime and the rivers are running and I'm working up a little bit of shtick about water for the show. Water molecules are among the smallest, and one goal of the piece is to relate the size...
  24. wildonion

    Kinematic viscosity for water on Mars

    Hi - I am trying to understand the relationship between atmosphere pressure, viscosity, and density - specifically water. Is there are way to estimate a range of dynamic viscosity and density values based on varying atmospheric pressures and/or temperature that I could use on any planet. Thanks...
  25. J

    Ball floating on the surface of water

    Homework Statement Homework EquationsThe Attempt at a Solution When air is evacuated , atmospheric pressure pushing down the cork is eliminated , cork should rise a little i.e option b) . This is incorrect . What am I missing ?
  26. J

    Why Is There a Limit to Drinking Water Through a Straw?

    Homework Statement Homework EquationsThe Attempt at a Solution My understanding is that while sucking , the pressure inside the straw decreases .Atmospheric pressure on the water surface pushes the water down such that it rises in the straw, into the mouth . I don't understand how there...
  27. I

    How is water produced in photosynthesis?

    I have looked everywhere, but most of the sources say water is not produced (which is not true), and some sources, such as my biology textbook, simply say it is produced. I know for every 6CO2 put into the Calvin cycle, 6 oxygen atoms are put into 2*G3P. Where do the other 6 leave the Calvin...
  28. Stephenk53

    Water resistance in a flashlight

    I recently made a flashlight/ laser pointer that can charge my phone, and I was wondering as to how I could make it resistant to the rain while allowing the top to be removable to switch out the batteries and make repairs. I also plan on making it attach to my arm like a gauntlet. So how could I...
  29. M

    Inteference Fringes of Double Slit Experiment in Water

    Homework Statement Suppose a double-slit experiment is immersed in water (with an index of refraction of 1.33). When in the water, what happens to the interference fringes? Homework Equations λ = λ0 / n y = (λmL) / d d = distance between slits L = distance to viewing screen n = index of...
  30. WhiteWolf98

    Determining the coefficient of viscosity of water (Graph Problem)

    Homework Statement So, the question is based around an experiment to determine the coefficient of viscosity for water (by capillary flow). Part of the experiment involved producing a graph of Q against h. This graph is supposed to be linear, and is supposed to pass through the origin. As can be...
  31. P

    Calculating Heat Transfer in a Water Bath with a Changing Volume and Temperature

    Homework Statement A cylinder is fitted with a piston and is in thermal contact with a heat bath at 273K. Initially the volume in the cylinder is filled with 10kg of pure H2O and about half of this is liquid and the other half is solid. The piston is lowered so as to reduce the volume by 2 ×...
  32. P

    Calculating Speed and Force in Water Jet Impact | Fluid Mechanics Homework

    Homework Statement "A jet of water issues from a nozzle, of diameter h_1=0,102 m (and depth b=1 m), at a speed U_1=2,02 m/s. The jet strikes a flat plate of mass M=2,05 kg, as shown in figure, and it breaks into two jets of equal speed and diameter h_2=0,122 m and h_3=0,102 m. Determine the...
  33. G

    Plastic particles found in bottled water

    So recently news broke about there being plastic particles/contaminants inside major brand water bottles (plastic), so since I don't drink bottles water but use some plastic bottles myself to fill in some fresh water from the local forest I then wonder how did the plastic particles got in the...
  34. zul8tr

    Hydrostatic force on identical containers filled with equal volumes of water

    In the sketch are 2 identical containers filled with equal volumes of water. Which has a greater absolute vertical force only on the conical wall and by what relative amount? Not a classroom or homework problem.
  35. EF17xx

    Tuning fork standing wave in a water pipe

    Homework Statement The question is as follows: The distance between the two positions of maximum loudness is x What is the wavelength of the sound emitted by the tuning fork ? A. x/2 B. x C. 3x/2 D. 2x the correct answer is answer D. Homework Equations Pipe with two ends open λn=...
  36. P

    Where can I find water vapor images?

    I am searching for images of the daytime sky taken within the water vapor absorption bands at 940nm, 1600 nm, 1860 nm, 2700 nm or 2900 nm. Specifically I am trying to see if multispectral images of in-band and adjacent out-of-band photos could be subtracted to show areas of slight water vapor...
  37. EF17xx

    Unpolarised light incident on a water surface

    Homework Statement Homework Equations n1/n2 = (sinθ2)/(sinθ1) = v2/v1 The Attempt at a Solution Moving from a lower refractive index to a higher refractive index. ( Lower density to higher density means faster speed to slower speed) The answer is answer B, I don't understand why.
  38. J

    Random Walk of KMnO4 in Water: Why Do We Observe Non-Probabilistic Behavior?

    I had a question regarding the random walk problem in statistical mechanics. If I drop, say, one molecule of KMnO4 in a beaker of water, what we generally observe (spread of KMnO4 to the ends of the beaker) is different from what we should get from probabilistic assumptions. I must be going...
  39. P

    How would you solve the water abundance XPrize?

    Hi everyone, This was the criteria for the competition: The Water Abundance Prize tasks competing teams with developing technologies that can harvest 2,000 liters (528 gal) of water from the atmosphere each day, using only renewable energy at a cost of no more than two centers per liter (0.26...
  40. G

    Air pressure holds coaster on glass: What if only half full?

    Hi. If I fill a glass with water up to the top and close it with a coaster, I can turn it upside down without the coaster falling off and spilling everything. Usually, this is explained with the atmospheric air pressure being bigger than the pressure of the water inside the glass (hence, it...
  41. K

    Finding power as a function of time in transferring water

    Homework Statement A completely filled cylindrical tank of height H contains water of mass M. At a height h above the top of the tank there is another wide container. The entire water from the tank is to be transferred into the container in time T such that level of water in tank decreases at a...
  42. MermaidWonders

    MHB Analysing Salt Buildup in Water Reservoirs

    Alright... Here's one I encountered today. Suppose the water reservoir holds 100 million gallons of water and supplies a city with 1 million gallons a day. The reservoir is partly refilled by a spring which provides 0.9 million gallons a day and the rest of the water, 0.1 million gallons a...
  43. A

    Why Does Alka-Seltzer Acidify Water but Act as an Antacid?

    Hi everyone. I was testing the pH of water that had alka seltzer placed in it. I used Bromothymol blue indicator to see the pH. The color changed to yellow, which suggests that the water was now acidic. I assume this is because of the CO2 bubbles that form which can acidify the H2O. Am I...
  44. R

    Calculating water pressure and the required mass of water

    Basically what I'm trying to do is calculate the amount of water it would take to generate a given pressure at the water tap. Or to put it more simply I'm trying to figure out where the water line is damaged, well more for fun then actually being practical. The water system is simply a well on...
  45. kyphysics

    Study: Major Bottled Water Brands Contaminated w/ Plastic

    https://www.yahoo.com/lifestyle/top-bottled-water-brands-contaminated-plastic-particles-report-013209098.html What conclusions should we draw? I drink exclusively bottled water too. Can't remember last time I had it unbottled.
  46. ConnorJohn

    Question about lifting water through a water pipe.

    Hello! First post, hope you all can help me out. I’m a peace corps volunteer in Nepal and am trying to implement drip irrigation for my school garden, since this season, we get water for about 30 minutes in the morning through a tap that is “always open.” The water that comes has some pressure...
  47. ConnorJohn

    Question about lifting water through a water pipe

    Hello! First post, hope you all can help me out. I’m a peace corps volunteer in Nepal and am trying to implement drip irrigation for my school garden, since this season, we get water for about 30 minutes in the morning through a tap that is “always open.” The water that comes has some...
  48. Q

    Water cooling for trout ponds in the South African summer

    Hi I am is desperate need of advice, I live in sunny South Africa have 10 trout dams on an estate for catch and keep purposes. Each dam is approximately 2,5 Acres and 3 metres +/- 10FT deep in certain areas. The main issue is in summer the water temperature is sitting at 28deg celsius 82...
  49. Moayd Shagaf

    Equation for Water Flow Over Pipe Circular Hole

    suppose a water falling from pipe that above the ground with 5 meters, what is the equation that describe the level of water ( h) from pipe the hole at every moment of time? consider the pipe hole is circle .
  50. NoahCygnus

    Calculation of the change in internal energy of water

    Homework Statement If water vapor is assumed to be a perfect gas, molar enthalpy change for vaporization of 1 mol of water at 1 bar and 100 C is 41 kJ/mol . Calculate the internal energy, when 1 mol of water is vaporized at 1 bar pressure and 100 C. Homework Equations $$\Delta U = \Delta H =...
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