Chapter 1 Flashcards
(145 cards)
1
Q
it can be defined as the science of energy
A
thermodynamics
2
Q
can be viewed as the ability to cause changes
A
energy
3
Q
therme and dynamis meaning
A
heat and power
4
Q
law that states that energy can change from one form to another; energy cannot be created or destroyed
A
conservation of energy principle
5
Q
the change in the energy content of a body is equal to the difference between the energy __________ and energy _________
A
input and output
6
Q
is simply an expression of the conversation of energy principle, and it asserts that energy is a thermodynamic property.
A
first law of thermodynamics
7
Q
asserts that energy has quality as well as quantity, and actual processes occur in the direction of decreasing quality of energy.
A
2nd law of thermodynamics
8
Q
a substance consists of a large number of particles called _____________
A
molecules
9
Q
the macroscopic approach that does not require a knowledge of the behavior of individual particles is called _____________. It is also in direct and easy way.
A
classical thermodynamics
10
Q
A more elaborate approach, based on the average behavior of large groups of individual particles is called ______________
A
statistical thermodynamics
11
Q
Any physical quantity can be characterized by ____________
A
dimensions
12
Q
the magnitude assigned to dimension is called ________
A
units
13
Q
basic dimensions such as mass, length, and temperature are selected as _________
A
primary or fundamental dimensions
14
Q
dimensions such as velocity and volume which are expressed in terms of the primary dimensions are called ____________________
A
secondary or derived dimensions
15
Q
two sets of units that are used today
A
SI and English system
16
Q
also known as USCS (United States Customary System)
A
English System
17
Q
also known as the International System
A
SI
18
Q
is a simple and logical system based on a decimal relationship between the various units, and it is being used for engineering work including England.
A
SI (International System)
19
Q
has no apparent systematic numerical base
A
English system
20
Q
1 lbm = kg
A
0.454 kg
21
Q
formula of newton’s 2nd law
A
F=ma
22
Q
1 slug = lbm
A
32.174 lbm
23
Q
1 lbf = lbm ft/s^2
A
32.2
24
Q
1N = 1?
A
kg m/s^2
25
The weight of a unit volume of a substance is called the ____________
specific weight
26
specific weight formula
density x gravity
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a form of energy which can be defined as force times distance therefore it is Newton dot meter
Work
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1 J = 1?
1 N dot meter
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are identically equal to 1 and are unitless
unity conversion ratios
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is defined as a quantity of matter or a region in space chosen for a study
system
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the mass or region outside the system is called
surroundings
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the real or imaginary surface that separates the system from its surroundings is called
boundary
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consists of a fixed amount of mass, and no mass can cross its boundary. in this, energy can cross the boundary
closed system
34
other term of closed system
control mass
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energy and mass cannot cross the boundary
isolated system
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both mass and energy can cross the boundary
open system or control volume
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the boundaries of a control volume is called a _______. they can be real or imaginary.
control surface
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what forms the imaginary part of a control surface
entrance and exit areas
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any characteristic of a system is called a
property
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those that are independent of the mass of a system, such as temperature, pressure, and density.
Intensive properties
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temperature
pressure
density
Intensive properties
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those whose values depends on the size of the system
Extensive Properties
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mass
volume
momentum
Extensive Properties
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extensive properties per unit mass are called
specific properties
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it s defined as mass per unit volume
density
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density of water in SI
1000 kg/m^3 or 1 kg/L
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density of water in English
62.4 lbm/ft^3
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the reciprocal of density is the
specific volume
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defined as volume per unit mass
specific volume
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the ratio of the density of a substance to the density of some standard substance at a specified temperature.
specific gravity or relative density
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the weight of a unit volume of a substance is called
specific weight
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specific weight of water in SI
9.81 kN/m^3
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specific weight of water in English
62.4 lbf/ft^3
54
thermodynamics deals with ______________states. which implies a state in balance
equilibrium
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temperature is the same throughout the entire system
thermal equilibrium
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there is no change in pressure at any point of the system with time
mechanical equilibrium
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mass of each phase reaches an equilibrium level and stays there
phase equilibrium
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chemical composition does not change with time and there is no chemical reaction
chemical equilibrium
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temperature and specific volume are
independent
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temperature and pressure are
dependent
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any change that a system undergoes from one equilibrium state to another is called a
process
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the series of states through which a system passes during a process is called the ________ of the process
path
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when a process proceeds in such a manner that the system remains infinitesimally close to an equilibrium state at all times, it is called a
quasistatic or quasi-equilibrium process
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can be viewed as sufficiently slow process that allows the system to adjust itself internally
quasi-equilibrium process
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if piston was compressed suddenly, molecules will pile up in front of the piston creating a high-pressure region there. because of this pressure difference, the system can no longer be said to be in equilibrium, this makes the entire process ______________
non-quasi equilibrium
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often used to designate a process for which a particular property remains constant.
iso-
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is a process during which the temperature T remains constant
isothermal process
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pressure P remains constant
isobaric process
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specific volume V remains constant
isochoric or isometric process
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a system is said to have undergone a ________ if it returns to its initial state at the end of the process
cycle
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at the point when heat transfer stops, the two bodies are said to have reached ______________
thermal equilibrium
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states that if two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other.
zeroth law of thermodynamics
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two bodies are in thermal equilibrium if both have the same temperature reading even if they are not in contact
zeroth law of thermodynamics
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freezing point is also called as
ice point
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boiling point is also called as
steam point
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temperature scale that is independent of the properties of any substance or substances
thermodynamic temperature scale
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the thermodynamic temperature scale in SI is
Kelvin
78
boiling point of water in K
373
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boiling point of water in degrees C
100
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boiling point of water in degrees F
212
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freezing point of water in K
273
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freezing point of water in degrees C
0
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freezing point of water in degrees F
32
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absolute zero of water in K
0
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absolute zero of water in degrees C
-273
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absolute zero of water in degrees F
-459
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enable us to use a common basis for temperature measurements, and several have been introduced throughout history
temperature scales
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centrigade scale
celsius scale
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celsius scale is renamed after
A. Celsius
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Fahrenheit is renanamed after
G. Fahrenheit
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In celsius scale, ice and steam points were originally assigned the values _____ and _______
0 and 100
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Fahrenheit ice and steampoint
32 and 212
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temperature values are assigned at two different points
two-point scales
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it is developed in conjunction with 2nd law of thermodynamics
thermodynamic temperature scales
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thermodynamic temperature scale in SI
Kelvin
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Kelvin is named after
Lord Kelvin
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why is Rankine and Kelvin doesn't have degrees?
since their lowest temperature is absolute zero and they cannot be negative
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Celsius to Kelvin formula
K = deg C + 273.15
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Fahrenheit to Rankine
R = deg F + 460
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Kelvin to Rankiine
R = 1.8 K
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Celsius to Fahrenheit
deg F = 1.8 deg C + 32
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normal force exerted by fluid per unit area
Pressure
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pressure only deals with ?(gas, liquid, or solid)
gas and liquid
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counterpart of pressure in solids
normal stress
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unit of pressure
N/m^2 or Pascal
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1 Pa = ? N/m^2
1
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different pressure units
bar
standard atmosphere
kilogram-force per square centimeter
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1 bar = 1? Pa = ? MPa = ? kPa
10^5 Pa
0.1 MPa
100 KPa
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1 atm = ? Pa
101, 325 Pa
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1 kgf/ cm^2 = ? N/cm^2
9.807 N/cm^2
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10^5 Pa = bar
1
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0.1 MPa = bar
1
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100 KPa = bar
1
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101, 325 Pa = atm
1
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1 atm = bar
1.01325 bar
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1.01325 bar = atm
1
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1 kgf/ cm^2 = N/m^2
9.807 x 10^4 N/m^2
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1 kgf/ cm^2 = Pa
9.807 x 10^4 Pa
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1 kgf/ cm^2 = bar
0.9807 bar
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1 kgf/ cm^2 = atm
0.9679 atm
121
the actual pressure at a given position
absolute pressyre
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it is measured relative to absolute vacuum
absolute pressure
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difference between the absolute pressure and the local atmospheric pressure
gage pressure
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pressure below atmospheric pressure are called
vacuum pressures
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difference between the atmospheric pressure and the absolute pressure
vacuum pressure
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it is the negative gage pressure
vacuum pressure
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P gage =
P gage = P abs - Patm
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P vac =
P vac = P atm - P abs
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1 lb/ in^2 is also equivalent to 1?
psi
130
the ______________ value of the atmospheric pressure is used when getting the absolute pressure
local
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pressure due to height formula
density x gravity x height (pgh)
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P = Patm + Pgage
Pgage can be rewritten as?
pgh (density x gravity x height)
so, P = Patm + pgh
133
specific weight (y) formula
density x gravity (pg)
134
change in P = P2 - P1 = pg(change in h) = specific weight x change in height
△P = P2 - P1 = pg△h = y△h
135
△h is called?
pressure head
136
pressure in fluid increases _____________ with depth
linearly
137
for a given fluid, the vertical distance is sometimes used as a measure of pressure and it is called __________________
pressure head
138
commonly used to measure small and moderate pressure differences
manometer
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A fluid column can be used to measure pressure differences and a device based on this principle is called
manometer
140
consists of glass or plastic U-tube containing one or more fluids such as mercury, water, alcohol, or oil.
manometer
141
pressure increases (downward or upward?)
downward
142
two points at the same elevation in a continuous fluid at rest are at the (same or different?) pressure
same
143
The last principle is a result of
Pascals' Law
144
allows us to jump from one fluid column to the next in manometers without worrying about pressure change as long as we don't jump over a different fluid and the fluid is at rest
The last principle which is a result of Pascal's law
145
