# ME103: Thermodynamics

Unit 3: Energy Transfer Through Work, Heat, and Mass   For our purposes, energy is a substance that has the potential to change the state of a system, depending on its motion into and out of the defined area of analysis.  In this unit, we will learn to quantify and observe energy as it affects the studied area.

Energy is transferred into and around a system by work transfer and heat transfer.  Thermodynamics studies the transfer of work and heat in and out of systems and how it affects the properties of the systems.

This unit will take you approximately 20 hours to complete.

☐    Subunit 3.1: 12 hours

☐    Subunit 3.1.1: 3 hours

☐    Subunit 3.1.2: 3 hours

☐    Subunit 3.1.3: 3 hours

☐    Subunit 3.1.4: 3 hours

☐    Subunit 3.2: 4 hours

☐    Subunit 3.2.1: 4 hours

☐    Subunit 3.2.2: 4 hours

Unit3 Learning Outcomes
Upon successful completion of this unit, the student will be able to:
- Calculate kinetic energy, potential energy, internal energy, and total energy of a system. - Calculate enthalpy and specific heat for a system.

3.1 Energy   - Web Media: University of Oklahoma: Multimedia Engineering Thermodynamics, “Energy, Specific Heat, and Enthalpy: Theory” Link:  University of Oklahoma: Multimedia Engineering Thermodynamics, “Energy, Specific Heat, and Enthalpy: Theory” (HTML)

Instructions: Please read the entire webpage, which provides an overview of the concepts of energy, enthalpy, and specific heat.  Click on “Simulation” (Shockwave) on the top of the web page to study the simulation of a hand slapping a face.  This reading covers subunits 3.1.1-3.1.4.

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Instructions: Please watch the video, which discusses different types of energy.

3.1.1 What Is Energy?   3.1.2 Kinetic and Potential Energy   3.1.3 Internal Energy   - Web Media: KhanAcademy’s “First Law of Thermodynamics/ Internal Energy” Link: KhanAcademy’s “First Law of Thermodynamics/ Internal Energy” (YouTube)

Instructions: Please watch the video, which discusses internal energy and first law of thermodynamics.

Instructions: Please what the video, which discusses more on internal energy.  Which modes of energy are stored in a system?

3.1.4 Enthalpy and Specific Heat   3.2 Energy Transfer   3.2.1 Transfer Through Work   - Reading: North Carolina State University: Professor Boles’ Lecture Notes on Thermodynamics: “Chapter 3: Energy Transfer by Heat, Work, and Mass” Link: North Carolina State University: Professor Boles’ Lecture Notes on Thermodynamics: “Chapter 3: Energy Transer by Heat, Work and Mass” (PDF)

Instructions: Please click on “Study Guide for Chapter 3.”  Please read pages 3–10 to pages 3–26.  In this reading, you will learn about energy transfer through work.  In mechanics, work is defined as a force acting on a moving body.  Imagine, for example, you are trying to move your desk across the room.  You will probably find it difficult to push the desk across the floor, and will likely be tired when you are finished.  However, if you only pulled the desk out from the wall a few inches—say to slip a cord behind it—you would be much less exhausted when finished.  The first example requires more “work” than the second.  In this unit, you will also learn how to calculate work for several typical processes, including constant volume, constant pressure, constant temperature, and polytropic processes.

• Reading: University of Notre Dame: Professor J. M. Powers’ Lecture Notes on Thermodynamics: “Chapter 4: Work and Heat” Link: University of Notre Dame: Professor J. M. Powers’ Lecture Notes on Thermodynamics: “Chapter 1: Introduction to Thermodynamics” (PDF)

Instructions: Please read section 4.2 “Work.”  Go through example 4.5 on page 83 carefully.  What is the work associated with expansion or compression of a fluid?

3.2.2 Heat Transfer   - Reading: Queen’s University: Canada: Professor G. Ciccarelli’s Lecture Notes on Applied Thermodynamics: “Lectures 3-5: Work, Energy and Heat” Link: Queen’s University: Canada: Professor G. Ciccarelli’s Lecture Notes on Applied Thermodynamics: “Lectures 3-5: Work, Energy and Heat” (PDF)

`````` Instructions: Please download the PDF file for Lecture 3-5 and read
pages 29-30.  This reading will introduce you to basic concepts of
heat transfer.  Which characteristics are common between heat and
work?

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• Reading: North Carolina State University: Professor Boles’ Lecture Notes on Thermodynamics: “Chapter 3: Energy Transfer by Heat, Work, and Mass” Link: North Carolina State University: Professor Boles’ Lecture Notes on Thermodynamics: “Chapter 3: Energy Transer by Heat, Work and Mass” (PDF)

Instructions: Please click on “Study Guide for Chapter 3.”  Please read pages 3–2 to pages 3–10.  In this reading, you will learn about the three basic modes of heat transfer: convection, conduction, and radiation. Which heat transfer mode is the most efficient?  Identify heat transfer modes involved in boiling water on a stove.  Which property of a system changes when heat is transferred at constant pressure?