ES346 Fall 2012 Exam 2
Name or student #:
Show all work for full credit. Extra paper is available. Circle final answers, and include units.
(10 points) Circle all the following that are true about the polytropic process Pvn = constant.
(a) A polytropic pr

ES346 Fall 2012 Exam 1
Name or student #: answers
Show all work for full credit. Extra paper is available. Circle final answers, and include units.
(10 points) A mixture of saturated liquid and saturated water vapor has a quality of 0.25 and a
temperature

ES346 Fall 2013 Exam 1
Name or student #: solutions
Show all work for full credit. Extra paper is available. Circle final answers, and include units.
(10 points) A 4-ft3 rigid tank contains 2.0-lbm of water at 250 psia. Circle all the following statements

ES346 Fall 2013 Exam 2
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solutions
Show all work for full credit. Extra paper is available. Circle final answers, and include units.
(10 points) An ideal gas is expanded to twice its initial volume by reducing the pressure 60% (i.e.
V2 =

Lecture-6 Examples
Air enters a 28-cm diameter pipe steadily at 200 kPa and 20C with a velocity of
5 m/s. Air is heated as it flows, and leaves the pipe at 180 kPa and 40C.
Determine (a) the volume flow rate of air at the inlet, (b) the mass flow rate of

ES346 Homework Chapter 5
Problem 5.7
Air enters a nozzle steadily at 2.21 kg/m3 and 40 m/s and leaves at 0.762 kg/m3 and 180 m/s. If the inlet
area of the nozzle is 90 cm2, determine (a) the mass flow rate through the nozzle, and (b) the exit area
of the

Name:
HW #03
Due: 02/14/2012
ES 346
Solution Set
2-32
1 of 9
Problem:
The force F required to compress a spring a distance x is given by F F0 = kx
where k is the spring constant and F0 is the preload. Determine the work required
to compress a spring whose

Name:
HW #01
Due: 01/31/2012
ES 346
Solution Set
1-94
1 of 12
Problem:
A lunar exploration module weighs 2800 N at a location where g = 9.8 m/s2.
Determine the weight of this module in newtons when it is on the moon where g =
1.64 m/s2.
Solution:
Use Newt

Name:
HW #02
Due: 02/07/2012
Solution Set
ES 346
2.6
1 of 9
Problem:
Calculate the total kinetic energy, in Btu, of an object with a mass of 15 lbm when
its velocity is 100 ft/s.
Solution:
Using the appropriate conversion factor from the text, total kinet

Lecture 20
ES 346
Basic Thermodynamics
1 of 1
Class meeting 20 will be used to take Exam #2.
o This exam will cover material covered since Exam #1.
This basically consists of the material in Chapters 4 & 5 of
the text.
The material covered in Lectures 12

ES 346
Basic Thermodynamics
Lecture 21
1 of 1
Lecture period 21 will be spent reviewing the solutions to Exam #2.
o This will also be a good time to discuss any questions concerning
1st Law analysis of systems.
o Next
lecture
well
begin
to
investigate
the

ES 346
Basic Thermodynamics
Lecture 18
Reminder:
1 of 10
Exam #2 is next Tuesday during our 20th class meeting
period.
o Exam #2 will cover all material covered since Exam #1. However,
the new material has built on the material covered in the 1st exam.
So

ES 346
Basic Thermodynamics
Lecture 24
1 of 10
We noted that one aspect of the 2nd Law is that processes tend to operate
in a specific direction but not in the opposite direction.
o This leads us to the concept of a process being irreversible or
reversibl

ES 346
Basic Thermodynamics
Lecture 17
1 of 11
Lets continue with our investigation of 1st Law analyses of open systems.
o With open systems, we need to be concerned with the energy
entering and leaving our systems just as we did with closed
systems.
o We

ES 346
Basic Thermodynamics
Lecture 22
1 of 11
We now introduce the 2nd Law of Thermodynamics.
o The 1st Law of Thermodynamics stated that energy must be
conserved during a process.
By inference, the 1st Law states that energy exists.
o The 2nd Law tells

ES 346
Basic Thermodynamics
Lecture 27
1 of 5
Lets look at a few example problems:
Problem:
A heat engine, whose thermal efficiency is 40 percent, uses a hot
reservoir at 1300 and a cold reservoir at 500 Calculate the entropy
R
R.
change of the two reserv

ES 346
Basic Thermodynamics
Lecture 25
1 of 9
In our investigation of the 2nd Law to-date, weve concentrated on entire
cycles and devices running in cycles.
o Recall that cycles are comprised of individual processes.
o However, we havent looked closely at

ES 346
Basic Thermodynamics
Lecture 23
1 of 8
Last time we introduced the 2nd Law of Thermodynamics. We noted that it
had several implications for the study of energy, energy transfer, and
energy transformation. That is, the study of Thermodynamics. And a

ES 346
Basic Thermodynamics
Lecture 12
1 of 9
For the next several weeks, well look more closely at 1st Law analyses of
thermodynamic systems.
o Remember, we define the system in such a way as to help us to
analyze the problem/device in which we are inter

ES 346
Basic Thermodynamics
Lecture 10
1 of 3
Reminder: Exam #1 is Thursday.
o It will cover material from Chap. 1 3 of the text, lectures 1 thru 9
of the class schedule, and the associate reading and homework
assignments.
o You will need a copy of the Pr

ES 346
Basic Thermodynamics
Lecture 11
1 of 1
Class meeting 11 will be used to take Exam #1.
o It covers material from Chap. 1 3 of the text, lectures 1 thru 9 of
the class schedule, and the associate reading and homework
assignments.
o You will need a co

Lecture 08
ES 346
Basic Thermodynamics
1 of 11
Last time we introduced Phase Diagrams for a pure substance. One such
diagram was the T-v Diagram as shown below.
o The Phase Diagram for a substance allows us to see:
The vapor dome.
The vapor dome is bounde

ES 346
Basic Thermodynamics
Lecture 13
1 of 11
Were taking a closer look at 1st Law analyses of closed systems.
Last time we looked at several processes that might occur in/on a closed
system. We considered:
o A constant volume process.
o A constant press

ES 346
Basic Thermodynamics
Lecture 14
1 of 3
From the results of Exam #1, it is apparent that we need to spend some
additional time on:
o General problem solving techniques.
o The importance of using complete, explicit dimensional analysis in
problem sol

Lecture 09
ES 346
Basic Thermodynamics
1 of 6
Reminder: Exam #1 will be next Thursday.
o It will cover the material from chapters 1 3 of the text. And the
material covered in Lectures 1 10 of the class schedule.
o It will be closed book.
You will need a c

Lecture 15
ES 346
Basic Thermodynamics
1 of 3
We will continue going over additional examples of energy balance
problems on closed systems.
Problem:
2-lbm of water at 500 psia initially fill the 1.5-ft3 left chamber of a partitioned
system. The right cham

ES 346
Basic Thermodynamics
Lecture 16
1 of 8
Today well expand our investigation of 1st Law analyses to include open
systems.
o Remember, the big difference between open and closed systems is
that an open system allows mass to cross the system boundary.

ES 346
Basic Thermodynamics
Lecture 19
1 of 6
Lets conclude our investigation of 1st Law analyses of open systems by
looking at unsteady-flow processes.
o For steady-flow processes, we restricted ourselves to systems that
did not permit the mass within th

ME265Introductionto
ThermalSciences
Lecture 4
PROPERTIES OF PURE SUBSTANCES
PURESUBSTANCE
A substance that has a fixed chemical composition throughout is called
a pure substance. Water, nitrogen, helium, and carbon dioxide, for
example, are all pure subst

ES 346
Basic Thermodynamics
Lecture 28
1 of 5
In preparation for the Final Exam, lets continue to look at some example
problems.
Problem:
Steam at 6 MPa and 500 enters a two-stage adiabatic turbine at a rate
C
of 15 kg/s. Ten percent of the steam is extra