1. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 1 The First Law of Thermodynamics FIRST LAW OF THERMODYNAMICS

2. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 2 The First Law of Thermodynamics Mechanical Work Out Heat Loss, (W) Motor Electrical Power Input (W) m z

3. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 3 The First Law of Thermodynamics Adiabatic work System Work Transfer Surroundings Adiabatic Boundary

4. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 4 The First Law of Thermodynamics Equivalence of adiabatic processes Any adiabatic path can be used to connect the two states, and all adiabatic paths between the states will require the same amount of work transfer. State 1 State 2

5. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 5 The First Law of Thermodynamics First Law Statement The adiabatic work done on a closed system to connect two equilibrium states is independent of path.

6. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 6 The First Law of Thermodynamics The First Law Work done by the system is positive by convention.

7. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 7 The First Law of Thermodynamics Internal energy, U Work done by the system is positive by convention.  KE 1-2 = 0, and  PE 1-2 = 0.

8. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 8 The First Law of Thermodynamics State 1 State 2 Experimentally base, and never refuted by experiment or theory. Adiabatic Processes

9. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 4 Module 5 Slide 9 The First Law of Thermodynamics Key concepts and terms Adiabatic Work Transfer Total Energy, E Expansion Process First Law of Thermodynamics Internal Energy, U Path independence Quasistatic process Shaft Work