Physics Chapter 5: Fluids

Question 1

Poiseuille’s law (in relation to Q)

Answer 1

Q = flow rate. Applies to laminar flow, accounting for viscosity

Question 2

Poiseuille’s law (in relation to P)

Answer 2

Applies to laminar flow, accounting for viscosity

Question 3

Continuity Equation

Answer 3

Within a closed system, the flow rate of a liquid is constant

Question 4

Narrower tube has a _________ velocity and _________ pressure

Answer 4

Higher, lower

Question 5

Narrower tube has _________ pressure

Answer 5

Lower

Question 6

Higher velocity means __________ pressure

Answer 6

Lower

Question 7

Venturi effect describes what relationship

Answer 7

Narrower tube = lower pressure

Question 8

Archimedes principle

Answer 8

Question 9

Flow Rate

Answer 9

Volume of fluid passing by a specific point per unit time Q = A*v

Question 10

Poiseuille’s Law definition

Answer 10

describes the flow rate of a fluid through a cylindrical pipe under laminar (smooth) flow conditions

Question 11

What does the heart do when blood vessels constrict

Answer 11

it has to pump harder to maintain pressure because according to Poiseuille’s law, pressure change and radius are inversely proportional

Question 12

1atm = ____ kPa = ______ mmHg

Answer 12

101 kPa, 760mmHg

Question 13

Fluid pressure changes with depth are assumed to be linear. Why isn’t this the same for atmospheric pressure?

Answer 13

Volume of air isn’t constant.

Hydrostatic pressure for liquids is linear because as depth changes, the density of the liquid remains relatively constant. Gases, however, are compressible, so volume is affected by changes in pressure.

Question 14

Formula for density

Answer 14

Question 15

Density of water

Answer 15

Question 16

Specific Gravity

Answer 16

Question 17

Basic formula for pressure

Answer 17

P = F/A

Question 18

Pressure when submerged in a fluid

Answer 18

Question 19

Absolute Pressure

Answer 19

Question 20

Gauge Pressure

Answer 20

Question 21

% of object submerged

Answer 21

Question 22

Archimede’s principle

Answer 22

Question 23

Mechanical advantage of a hydraulic lift

Answer 23

Idea is that the same volume of fluid is being moved, force necessary depends on area

Question 24

What is surface tension?

Answer 24

caused by uneven intermolecular interactions @ interface between 2 surfaces (adhesive and cohesive forces)

Question 25

If adhesive forces to wall of a container are stronger than cohesive forces within a molecule what happens?

Answer 25

concave meniscus (water)

Question 26

If cohesive forces within a molecule a are stronger than cohesive forces to the walls of a container what happens?

Answer 26

Convex meniscus (mercury)

Question 27

Viscosity

Answer 27

Resistance to flow (resistance to deformation by stress)

Question 28

Bernoulli's law

Answer 28

Applies to ideal fluids with laminar flow and NO viscosity

Question 29

Continuity equation is due to

Answer 29

the incompressibility of liquids

Question 30

Pitot tube can be used to calculate what?

Answer 30

Velocity of a fluid

Question 31

What is this an example of?

Answer 31

The oxygen pressure is the sum of the oxygen static pressure P and the oxygen flow pressure ½ ρv2. In the area of the mask openings, Pair = P + ½ ρv2, thus Pair > P. Air enters the mask because the static pressure of the air is larger than the static pressure of the oxygen that flows in the mask. This is the Venturi effect, and the mask is called the Venturi mask.

Question 32

P term is what?

Answer 32

Absolute pressure. so if open on one end, it would be equal to atmospheric pressure. if closed, If the fluid is inside a closed system, 𝑃 P could be higher or lower than atmospheric pressure, depending on the conditions

Question 33

Why does fluid rise up in a pipet?

Answer 33

Question 34

Answer 34

A) Use formula P=ρgh DON"T use archimedes (that's for force) F=m×g=(V×ρ)×g