Fluids

Question 1

fluids

Answer 1

are substances that have the ability to flow and conform to the shape of their containers.
Can exert perpendicular forces, but cannot exert shear (tangental) forces
liquids and gases are the two phases of matter that are fluids

Question 2

solids

Answer 2

do not flow and they retain their shape regardless of their containers

Question 3

Density

Answer 3

mass per unit volume of a substance

p=m/v .

Question 4

pressure

Answer 4

defined as a measure of force per unit area; it is exerted by a fluid on the walls of its container and on objects placed in the fluid

• scalar quantity, magnitude with no direction
• pressure exerted by gas on wall of container will always be perpendicular.
• P=F/A

Question 5

absolute pressure

Answer 5

is the sum of all pressure at a certain point within a fluid; it is equal to the pressure at the surface of the fluid (usually atm) plus the pressure due to the fluid itself .

P=P0+pgz . z is depth of object

Question 6

gauge pressure

Answer 6

the name for the difference between absolute pressure and atm pressure. In liquids, gauge pressure is caused by the weight of the liquid above the point of measurement.

Pgauge = P- Patm = (P0 +pgz) - P atm

Question 7

Pascul’s principle

Answer 7

states that a pressure applied to an incompressible fluid will be distributed undiminished throughout the entire volume of the fluid.
P=F1/A1 = F2/A2
F2 = F1 (A2/A1)

Question 8

Hydraulic machines

Answer 8

operate based on the application of Pascal’s principle to generate mechanical advantage.

Question 9

Arichimedes’ principle

Answer 9

governs the buoyant force. When an object is placed in a fluid, the fluid generates a buoyant force against the object that is equal to the weight of the fluid displaced by the object.

• direction of force is always opposite to the direction of gravity
• max buoyant force is larger than the force of gravity on object, the object will float. this will be true if object less dense than fluid
• Max is smaller, the object will sink. True if the object is more dense than the fluid it is in.

Question 10

Cohesive forces of fluids

Answer 10

force between molecules of the same fluids. Gives rise to surface tension.

Question 11

Adhesive

Answer 11

forces between molecule and other materials .

Question 12

Fluid dynamics

Answer 12

set of principles regarding actively flowing fluid

Question 13

viscosity

Answer 13

measurement of fluid’s internal friction. Viscous drag is a nonconservative force generated by viscosity.

Question 14

What are the two flows of fluids

Answer 14

Laminar flow and turbulent flow

Question 15

laminar flow

Answer 15

is the smooth ad orderly, and is often modeled as layers of fluid that flow parallel to each other.

Question 16

Turbulent flow

Answer 16

rough and disorderly. Can cause formation of eddies, which are swirls of fluid varying sizes occurring typically on the downstream side of an obstacle.

Question 17

continuity equation

Answer 17

is a statement of the conservation of mass as applied to fluid dynamics
Q = v1A1 = v2A2

Question 18

Bernoulli’s equation

Answer 18

is a expression of conservation of energy for a flowing fluid. This equation states that the sum of static pressure and the dynamic pressure will be constant between any two point in a closed system.
P1 + 1/2 pv1^2 + pgh1 = P2 + 1/2 pv^2 + pgh2 .

Question 19

Venturi effect

Answer 19

for horizontal flow, there is an inverse relationship between pressure and speed, and in a closed system, there is a direct relationship between cross-sectional area and pressure exerted on the walls of the tube.

Question 20

Circulatory system is what kind of system

Answer 20

behaves as a closed system with non-constant flow

Question 21

Resistance decreases as the total cross-sectional area…

Answer 21

increases

Question 22

arterial circulations i primarily motivated by…

Answer 22

the heart

Question 23

venous circulation has three times the volume of arterial circulation and is motivated by…

Answer 23

skeletal musculature and expansion of the heart

Question 24

inspiration and exportation create a pressure gradient for…

Answer 24

respiratory system and circulatory system

Question 25

Air at the alveoli has essentially ____ speed

Answer 25

zero

Question 26

Buoyant force equation

Answer 26

F buoy = p fluid V fluid displaced g = p fluid V submerged g

Question 27

Poiseuille’s law

Answer 27

Q = πr^4ΔP/8nL

Question 28

critical speed

Answer 28

vc=NR n/ pD

Question 29

specific gravity

Answer 29

SG = p/1 g/cm^3 .

Question 30

Weight of a volume of fluid

Answer 30

Fg = pVg . Density of fluids are usually compared to pure water

Question 31

dynamic pressure

Answer 31

1/2pv^2 . pressure associated with movement of pressure, kinetic energy of fluid .

Question 32

gravitational potential energy

Answer 32

pgh

Question 33

energy density

Answer 33

ratio of energy per cubic meter .