Topic 2B

Question 1

Density equation

Answer 1

Density = mass/volume

Question 2

Specific gravity equation

Answer 2

specific gravity = density of material / density of water

Question 3

buoyancy

Answer 3

it’s the ratio of the density of a substance to the density of a reference substance; equivalently, it’s the ratio of the mass of a substance to the mass of a

reference substance for the same given volume”

Question 4

Archimedes principle

Answer 4

the buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid the body displaces
Fobject = Wfluid

Question 5

Pressure formula

Answer 5

Pressure = force/ unit area

Question 6

Hydrostatic pressure formula

Answer 6

Fluid pressure = (fluid density)(acceleration d/t gravity)(fluid depth)

Question 7

Pascal’s Principle/Pascal’s Law

Answer 7

applies to static fluids and takes advantage of the height dependency of pressure in static fluids. Pascal’s Principle can be used to exploit pressure of a static liquid as a measure of energy per unit volume to perform work in applications such as hydraulic presses.

Question 8

Viscosity formula

Answer 8

Viscosity = [(Force)(distance b/t the plates)] / [(constant velocity)(Area of the plate)]

Question 9

Poiseuille flow

Answer 9

pressure-induced flow in a long duct, usually a pipe. It is assumed that there is a laminar flow of an incompressible fluid of viscosity η

Question 10

Flow rate Q- Poiseuille’s

Answer 10

Question 11

Volumetric flow rate- Q,v, A and Q, V, t

Answer 11

Q=velocity of fluid x area of the cross-section of the space the fluid is moving through

Q = Volume/ elapsed time

Question 12

Reynolds number (NR)

Answer 12

the ratio of inertial forces to viscous forces within a fluid which is subjected to relative internal movement due to different fluid velocities; dimensionless quantity It can reveal whether flow is laminar or turbulent. For flow in a tube of uniform diameter, the Reynolds number is defined as:
NR = [(2fluid densityspeed*tube radius)] / [(viscosity)]

Question 13

Reynolds number around what is laminar and around what is turbulent

Answer 13

around 2000 is laminar and around 3000 is turbulent and between 2000-3000 is unstable

Question 14

Surface tension

Answer 14

s proportional to the strength of the cohesive force, which varies with the type of liquid. It’s the reason why liquids form bubbles and droplets. The inward surface tension force causes bubbles to be approximately spherical and raises the pressure of the gas trapped inside relative to atmospheric pressure outside.

γ = force / unit length L exerted by a stretched liquid membrane:

Question 15

Cohesive forces

Answer 15

(IMF’s within a fluid) are stronger, then surface of fluid is convex

Question 16

Adhesive forces

Answer 16

(IMF’s between a fluid and the tube) are stronger, the surface of fluid is concave

Question 17

Bernoulli’s equation:

Answer 17

The relationship between pressure and velocity in fluids

Question 18

Situation where the fluid is static—that is, v 1 = v 2 = 0. In that case, we get

Answer 18

P2=P1 + density(g)(height1)

Question 19

Situation where the fluid moves but its depth is constant—that is, h 1 = h2 . Bernoulli’s equation becomes:

Answer 19

Question 20

Pitot tube

Answer 20

a horizontal tube that contains a U-shaped tube.

◦ The surface of the pitot tube has at least two openings, one of which faces directly into the fluid flow. The first opening encounters fluid with a velocity of zero. The pressure at this opening is equal to the static pressure exerted by the fluid.

Question 21

Venturi tube

Answer 21

A Venturi tube is a horizontal tube with a constricted region (decreased cross-sectional area) in its middle. It can be used to determine the velocity of a fluid that is flowing within it. This is in contrast to a pitot tube, which is used to determine the velocity of a fluid flowing past it.

Question 22

Ideal Gas Equation

Answer 22

(Pressure)(Volume) = (#moles)(Ideal gas constant)(Temperature)

Question 23

what are the 3 most common forms of R used as the ideal gas constant

Answer 23

8.3145 LkPa/Kmol; 0.0821 Latm/Kmol; 62.4 LmmHg/Kmol

Question 24

Boyle’s law

Answer 24

P1V1 = P2V2

Question 25

Charles’ law

Answer 25

V1/T1 = V2/T2

Question 26

Avogadro’s law

Answer 26

Volume * #moles = proportionality constant

Question 27

Kinetic Molecular Theory of Gases:

Answer 27

◦ The volume occupied by the individual particles of a gas is negligible compared to the volume of the gas itself.

◦ The particles of an ideal gas exert no attractive forces on each other or on their surroundings.

◦ Gas particles are in a constant state of random motion and move in straight lines until they collide with another body.

◦ The collisions exhibited by gas particles are completely elastic; when two molecules collide, total kinetic energy is conserved.

◦ The average kinetic energy of gas molecules is directly proportional to absolute temperature only; this implies that all molecular motion ceases if the temperature is reduced to absolute zero.

Question 28

Heat capacity/adiabatic index /thermal capacity

Answer 28

the measurable physical quantity that characterizes the amount of heat required to change a substance’s T by a given amount. An object’s heat capacity (C) is defined as the ratio of the amount of heat energy transferred to an object to the resulting ↑ in T of the object.

Question 29

heat energy equation

Answer 29

heat energy = mass * specific heat capacity * change in temperature