Pressure- force acting on a surface per unit area in a direction perpendicular to it is known as pressure on the surfae

Pressure- force acting on a surface per unit area in a direction perpendicular to it is known as pressure on the surfaePressure = Force/surface area

Units of pressure 1 pa = 1N/m21 bar= 105 pa 1 atm =1.013 x 105 pa1 atm = 76 cm-hg = 760mm-hg

Relative density orspecific gravityRelative density, orspecific gravity,is theratioof thedensity(mass of a unit volume) of a substance to the density of a given reference material. Specific gravity usually means relative density with respect to water.specific gravity = density of substance Density of water The two thigh bones (femurs), each of cross-sectional area10 cm2support the upper part of ahuman body of mass 40 kg. Estimate the average pressure sustained by the femurs

Pascal's lawor theprinciple of transmission of fluid-pressureis a principle influid mechanicsthat states that pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure variations (initial differences) remain the same

When an object is placed in a fluid, the fluid exerts an upward force we call the buoyant force. The buoyant force comes from the pressure exerted on the object by the fluid. Because the pressure increases as the depth increases, the pressure on the bottom of an object is always larger than the force on the top - hence the net upward force.Buoyancy = weight of displaced fluid.

Archimedes' principleindicates that the upwardbuoyant forcethat is exerted on a body immersed in afluid, whether fully or partially submerged, is equal to the weight of the fluid that the bodydisplaces.

Where F = Buoyant force of a given body, v = Volume of the displaced fluid g = acceleration due to gravityWe know that density=f-g. Herefis the density of the fluid andgis density of the body.Hence the formula can also be given as

Question1:A ball of mass 2 kg having diameter of 50 cm falls in the swimming pool. Calculate its buoyant force and volume of water displaced.Solution:Given: Mass of water, m = 2 kg, Diameter of ball, d = 0.5 m r = 0.25 mVolume of sphere V =43r3=430.253

= 0.0208 m3

Hence the density is given by=MassVolume =2kg0.0208m3 = 96 kg/m3.

The force is given by F = mg. Hence buoyant force isF = 2 kg9.8 m/s2= 19.6 N

The archimedes formula is given by F =g Vdisp

Hence the Volume of displaced fluid is Vdisp=Fg =19.6969.8 = 0.0208 m3

Hence volume of given body = Volume of displaced liquid.

A crown made of gold and copper weighs 210 gm in air and 198 gm in water. The weight of gold in crown is(a) 93 gm (b) 100 gm (c) 150 gm (d) 193 gmGiven: density of gold = 19.3 gm/cm3 and density of copper 8.5 gm/cm3

Acontinuity equationin physics is anequationthat describes the transport of aconserved quantity. Sincemass,energy,momentum,electric chargeand other natural quantities are conserved under their respective appropriate conditions, a variety of physical phenomena may be described using continuity equations.

Where:Q = the volumetric flow rateA = the cross sectional area of flowV = the mean velocity

A statement of the conservation of energy in a form useful for solving problems involving fluids. For a non-viscous, incompressible fluid in steady flow, the sum of pressure, potential and kinetic energies per unit volume is constant at any point.

Water at a gauge pressure of 3.8 atm at street level flows in to an office building at a speed of 0.06 m/s through a pipe 5.0 cm in diameter. The pipes taper down to 2.6cm in diameter by the top floor, 20 m above. Calculate the flow velocity and the gauge pressure in such a pipe on the top floor. Assume no branch pipe and ignore viscosity.

Solution:

By continuity equation:

v2= (A1v1) / A2= ( (5.0 / 2)2(0.60) ) / ( (2.6 / 2)2)

v2= 2.2 m/s

By Bernoullis Equation:

P1+ gh1+ (v1)2= P2+ gh2+ (v2)2 (Po = atmospheric pressure)

P2= (3.8 x Po) + Po + (1000)(0.6)2 (1000)(9.8)(20) (1000)(2.2)2

P2= 2.8 x 105Pa

ViscosityViscosity is a measure of the resistance of a fluid to deformation under shear stress.It is commonly perceived as "thickness", or resistance to pouring.Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction.Thus, water is "thin", having a low viscosity, while vegetable oil is "thick" having a high viscosity.

coefficient of viscositythemeasureoftheviscosityofafluid,equaltotheforceperunitarearequiredtomaintainadifferenceofvelocityofoneunitdistanceperunittimebetweentwoparallelplanesinthefluidthatlieinthedirectionofflowandareseparatedbyoneunitdistance:usuallyexpressedinpoiseorcentipoise.= F - coefficient of viscosity A.dv dxIts unit is dyn s/cm2