Skip to main content
UploadLanguage (EN)Support
BusinessMobileSocial MediaMarketingTechnologyArt & PhotosCareerDesignEducationPresentations & Public SpeakingGovernment & NonprofitHealthcareInternetLawLeadership & ManagementAutomotiveEngineeringSoftwareRecruiting & HRRetailSalesServicesScienceSmall Business & EntrepreneurshipFoodEnvironmentEconomy & FinanceData & AnalyticsInvestor RelationsSportsSpiritualNews & PoliticsTravelSelf ImprovementReal EstateEntertainment & HumorHealth & MedicineDevices & HardwareLifestyle
TL
Uploaded byTrina Marie Logroño
PPTX, PDF9,410 views

Fluids in Physics

The document outlines the objectives for a fluid physics chapter, focusing on the nature and behavior of fluids at rest and in motion. Key concepts include density, specific gravity, pressure, buoyancy, and fundamental principles such as Archimedes’ principle and Bernoulli’s principle. The text also provides definitions of relevant terms and sample problems related to fluid properties and calculations.

Engineering◦
Downloaded 98 times
FLUID Phys 22 – Physics 22
OBJECTIVES: At the end of the chapter, the students should be able to: 1. Explain the nature and scope of fluids, particularly: a) Fluids at rest b) Fluids in motion 2. Define term like density, specific gravity, pressure, buoyancy, viscosity, streamline, hydrostatics, and hydrodynamics. 3. Interpret and apply Archimedes’ principle, Pascal’s Law, and Bernoulli’s principle.
2. State reasons why a body floats, sinks or is suspended in a liquid. 3. Explain why some places have high water pressure while other places have low water pressure. 4. Solve problems on specific gravity, buoyancy, and pressure.
TERMS TO REMEMBER Fluid – A gas or liquid that flows. Density – Mass per unit volume. Specific gravity – The ratio of the density of a substance to that of a standard. Pressure – Force applied per unit area. Standard pressure – Pressure exerted by a column of mercury exactly 760 mm high. Total force – The force acting against the entire area of a surface Buoyant force – The upward force which is exerted by any fluid on a body immersed in it.
Gauge pressure – Pressure above or below atmospheric pressure. Hydraulic pressure – A hydraulic device for multiplying force or speed. Manometer – An instrument for measure pressure Hydrometer – A device for measuring the specific quantity of a liquid. Venturi meter – A device used to calculate the speed of fluid in a horizontal tube from the difference in pressure in the vertical tube.
FLUIDS AT REST  Matter is classified as solid, liquid or gas.  Liquid and gases are frequently grouped together as fluids, since they flow readily and do not resist shearing stresses.  Fluids at rest are liquids or gases in a container that are not allowed to flow.  If the fluids are at rest, the study of them is called fluid statics.  If the fluids are in motion, where pressure forces are not considered, the study of them is called fluid Kinematics.  If the fluids are in motion and the pressure forces are considered, the study of them is called fluid dynamics.
Density (D) The “mass per unit volume” is mass density. Hence, it has units of kilograms per cubic meter The mass density of water at 4oC is 1000 kg/m3 while it is 1.20 kg/m3 for air at 20oC at standard pressure. VVDm V m D 
Density: Example #1 A quantity of helium gas at 0°C with a volume of 4.00 m3 has a mass of 0.712 kg at standard atmospheric pressure. Determine the density of this sample of helium gas? ? 712.0 00.4 3    D kgm mV 3178.0 00.4 712.0 3 m kg m kg D V m D  
Specific Weight or Weight Density (γ)  It is the ratio between the weight if a fluid to its volume.  It is also weight per unit volume of a fluid.  Its unit is N/m3.  Water at 20 oC has a specific weight of 9.79 kN/m3  g  r g ( in terms of mass density) VVDm V w Y 
Specific Volume  It is defined as the volume of a fluid occupied by a unit mass or volume per unit mass of a fluid is called specific volume.  Specific Volume = Volume of the Fluid / Mass of the Fluid = 1/mass of the fluid/volume of the fluid = 1 / r
Specific Gravity (Sp.Gr) The ratio of specific weight of a given liquid to the specific weight of water at a standard reference temperature (4oC)is defined as specific gravity, Sp.Gr. The specific weight of water at atmospheric pressure is 9810 N/m3. 𝑆𝑃. 𝐺𝑅 = 𝛾 𝑠𝑢𝑏𝑠. 𝛾 𝑤𝑎𝑡𝑒𝑟 = 𝜌 𝑠𝑢𝑏𝑠. 𝜌 𝑤𝑎𝑡𝑒𝑟
Example #2 Carbon tetrachloride with a mass of 500 kg is placed in a container with 0.325 m3 in volume. a)Calculate the density (1538.46 kg/m3) b)Calculate its specific weight (15.1 kN/m3) c)Determine also its weight (4.9 kN)
Example #3 A certain liquid has a unit weight of 56 kN/m3. a)Compute the mass density (5708 kg/m3) b)Compute its specific volume (0.000175 m3/kg) c)Compute its specific gravity (5.71)
Pressure Is defined as force per unit area. The force is always perpendicular to the surface of the container. Pressure units are force units divided by area units, such as nt/m2, dyne/cm2, lb/ft2, and lb/in2. Pressure can also be expressed in atmospheres, where one atmosphere(atm) is equal to normal atmospheric pressure, which is approximately 1.013 x 105 nt/m2. VVDm A F P 
Rules in changing the height of liquid to another liquid  1. To change the height of any liquid to height of water. Rule : Multiply the height of the liquid by its own specific gravity.  2. To change the height of water to height of any liquid. Rule : Divide the height of water by the specific gravity of liquid where the height is to be found.  3. To change the height of the liquid in terms of another liquid. Rule : Multiply the height of one liquid by its own specific gravity and divide the product by the specific gravity of the liquid where the height is to be found.
Assignment 1. A pressure gauge at elevation 8 m. at the side of the tank containing a liquid reads 80 kPa. Another gauge at elevation 3 m. 120 kPa. Compute the following: a) Specific weight b) Density c) Specific gravity 2) The pressure in the tank is 50 psi. a) Find the equivalent pressure head of water. b) Find the equivalent pressure head of fuel oil with sp.gr = 0.92 c) Find the equivalent pressure head of nectar sp.gr = 2.94
Example # 4 A pressure in a given tank reads 277 mm of Hg. Specific gravity of Mercury(Hg) is 13.6. a)Determine the equivalent height of column of water. (3.77m) b)Determine the equivalent height of column of kerosene sp.gr = 0.82. (4.59m) c) Determine the equivalent height of column of nectar sp.gr = 2.94. (1.28m)