Exam 1 Conceptual Questions

Question 1

An ideal gas refers to a gas that ____ be modeled _______ the ideal gas equation with
an acceptable degree of accuracy.

Answer 1

can, using

Question 2

What is the ideal gas law

Answer 2

PV=mRT or PV=nRuT

Question 3

A _________ is the specific entity that is being studied or analyzed
by the engineer.

Answer 3

system

Question 4

______________ are considered anything that is not part of the system.

Answer 4

surroundings

Question 5

The ____________ is the imaginary surface that separates the system
from its surroundings.

Answer 5

boundary

Question 6

two kinds of stress are

Answer 6

normal (pressure) stress and shear stress

Question 7

________ is used to characterize friction like effects in flowing fluids

Answer 7

viscosity

Question 8

types of viscosity are

Answer 8

dynamic/absolute and kinematic

Question 9

low viscosity flows ______

Answer 9

easily

Question 10

Dynamic/Absolute viscosity is the____________ force per unit area required to move one horizontal ______ with
respect to another plane.

Answer 10

tangential, plane

Question 11

Kinematic viscosity is the ______ of absolute (dynamic) viscosity to ________

Answer 11

ratio, density

Question 12

No two fluids can have the same _________ viscosity, but they can have the
same ________ viscosity.

Answer 12

kinematic, dynamic

Question 13

The no-slip condition is a _________ condition in fluid mechanics that states that the __________ of a fluid in contact with a ______ surface is _______ to the velocity of the surface.

Answer 13

boundary, velocity, solid, equal

Question 14

Many experiments have shown that the surface of a liquid behaves like a stretched _____________. The material property that characterizes this behavior is __________ ________

Answer 14

membrane, surface tension

Question 15

The physical mechanism of surface tension is based on _________ _______, which is the attractive force between ____ molecules.

Answer 15

cohesive force, like

Question 16

Surface tension of water ___________ with temperature because thermal expansion moves the molecules ________ apart.

Answer 16

decreases, farther

Question 17

Surface tension is strongly affected by the presence of __________ or _________

Answer 17

contaminants or impurities

Question 18

The force between ____________
surfaces is called adhesion.

Answer 18

dissimilar

Question 19

_____ pressure is pressure above or below the local atmospheric pressure

Answer 19

gage

Question 20

________ pressure is the magnitude of the pressure below local atmospheric pressure

Answer 20

vacuum

Question 21

___________ pressure Δ𝑝 is the pressure difference between two
points

Answer 21

differential

Question 22

The pressure in a perfect vacuum is called __________ zero, and pressure measured
relative to this zero pressure is termed _________ pressure.

Answer 22

absolute, absolute

Question 23

_____________ is an instrument that is used to measure atmospheric pressure

Answer 23

barometer

Question 24

__________-______ Gage measures pressure by sensing the deflection of a coiled tube.

Answer 24

Bourdon-Tube

Question 25

____________ is a vertical tube, usually transparent, where a liquid rises in response to a positive gage pressure.

Answer 25

piezometer

Question 26

___________ is a device for measuring pressure by raising or lowering a column of liquid.

Answer 26

manometer

Question 27

_________ _________ (PT) is a device that converts pressure to an electrical signal.

Answer 27

pressure transducer

Question 28

In fluid statics, a fluid particle is in ____________ equilibrium because the weight of the fluid particle is in perfect _______ with the pressure force

Answer 28

hydrostatic, balance

Question 29

A _________ force is defined as an upward force (with respect to gravity on a body that is totally or partially ___________ in a fluid, either a liquid or gas.

Answer 29

buoyant, submerged

Question 30

Rises to the surface buoyancy

Answer 30

density of object is less than the fluid

Question 31

suspended body buoyancy

Answer 31

density of object equals density of fluid

Question 32

sinks to bottom buoyancy

Answer 32

density of object is more than density of fluid

Question 33

A __________ is the path of a fluid particle as it moves through a flow field.

Answer 33

pathline

Question 34

A ___________ is the line generated by a tracer fluid (dye) continuously injected into a flow field from a starting point

Answer 34

streakline

Question 35

A ____________ is a line that is tangent everywhere to the local velocity vector.

Answer 35

streamline

Question 36

When flow is unsteady, then the streamline, streakline, and pathline look ________

Answer 36

different

Question 37

When flow is steady, the pathline, streakline, and streamline look the ______ so long as they all pass through the same _______

Answer 37

same, point

Question 38

When the velocity field is represented in Cartesian components, the mathematical form is 𝐕 = 𝑢 𝑥, 𝑦, 𝑧,𝑡 𝐢 + 𝑣 𝑥, 𝑦, 𝑧,𝑡 𝐣 + 𝑤 𝑥, 𝑦, 𝑧,𝑡 𝐤 * The 𝑢 (𝑥, 𝑦, 𝑧, 𝑡) term represents the 𝑥 component of the velocity vector and 𝒊 is the unit vector in the __-_________. Similarly, 𝑣 and 𝑤 give the 𝑦 and 𝑧 ______________ of the velocity vector.

Answer 38

x direction, components

Question 39

Steady flow means that velocity at each location in space is ________ with time.

Answer 39

constant

Question 40

Unsteady Flow means the velocity is __________, at least at some points, in the velocity field. this happens from the presence of t in the velocity equation

Answer 40

changing

Question 41

In a ________ flow, the velocity is constant in magnitude and direction along a streamline at each instant in time.

Answer 41

uniform

Question 42

In _____________ flow, velocity changes along a streamline in magnitude, direction, or both.

Answer 42

nonuniform

Question 43

Laminar Flow * A well-________ state of flow in which adjacent fluid layers move smoothly with respect to each other. * Flow occurs in _______ or laminae.

Answer 43

ordered, layers

Question 44

Turbulent flow is _______ flow with eddies and mixing. * Higher Reynolds Number * Always ____ flow

Answer 44

unsteady, 3D

Question 45

Laminar flow is considered ____-________ flow where adjacent fluid ______ move smoothly with respect to each other. * Lower Reynolds Number * Steady or Unsteady * 1D, 2D, or 3D flow

Answer 45

well-ordered, layers

Question 46

A __________ tube (also known as a total head tube) is an open-ended tube directed ________ in a flow

Answer 46

open-ended, upstream

Question 47

The Pitot tube is used on aircraft to measure ______ * Measures the velocity by first measuring the difference between _____ and ________ pressures.

Answer 47

speed, static, stagnation

Question 48

A major advantage of the Pitot tube is that it can be used to measure velocity in a _________ pipe,

Answer 48

pressurized