## Table of Contents

**1 General Principles 3**

Chapter Objectives 3

1.1 Mechanics 3

1.2 Fundamental Concepts 4

1.3 Units of Measurement 7

1.4 The International System of Units 9

1.5 Numerical Calculations 10

1.6 General Procedure for Analysis 12

**2 Force Vectors 17**

Chapter Objectives 17

2.1 Scalars and Vectors 17

2.2 Vector Operations 18

2.3 Vector Addition of Forces 20

2.4 Addition of a System of Coplanar Forces 32

2.5 Cartesian Vectors 43

2.6 Addition of Cartesian Vectors 46

2.7 Position Vectors 56

2.8 Force Vector Directed Along a Line 59

2.9 Dot Product 69

**3 Equilibrium of a Particle 85**

Chapter Objectives 85

3.1 Condition for the Equilibrium of a

Particle 85

3.2 The Free-Body Diagram 86

3.3 Coplanar Force Systems 89

3.4 Three-Dimensional Force Systems 103

**4 Force System**

Resultants 117

Chapter Objectives 117

4.1 Moment of a Force–Scalar

Formulation 117

4.2 Cross Product 121

4.3 Moment of a Force–Vector

Formulation 124

4.4 Principle of Moments 128

4.5 Moment of a Force about a

Specified Axis 139

4.6 Moment of a Couple 148

4.7 Simplification of a Force and Couple

System 160

4.8 Further Simplification of a Force and

Couple System 170

4.9 Reduction of a Simple Distributed

Loading 183

**5 Equilibrium of a Rigid Body 199**

Chapter Objectives 199

5.1 Conditions for Rigid-Body Equilibrium 199

5.2 Free-Body Diagrams 201

5.3 Equations of Equilibrium 214

5.4 Two- and Three-Force Members 224

5.5 Free-Body Diagrams 237

5.6 Equations of Equilibrium 242

5.7 Constraints and Statical Determinacy 243

**6 Structural Analysis 263**

Chapter Objectives 263

6.1 Simple Trusses 263

6.2 The Method of Joints 266

6.3 Zero-Force Members 272

6.4 The Method of Sections 280

6.5 Space Trusses 290

6.6 Frames and Machines 294

**7Internal Forces 329**

Chapter Objectives 329

7.1 Internal Forces Developed in Structural

Members 329

7.2 Shear and Moment Equations and

Diagrams 345

7.3 Relations between Distributed Load, Shear,

and Moment 354

7.4 Cables 365

**8 Friction 387**

Chapter Objectives 387

8.1 Characteristics of Dry Friction 387

8.2 Problems Involving Dry Friction 392

8.3 Wedges 412

8.4 Frictional Forces on Screws 414

8.5 Frictional Forces on Flat Belts 421

8.6 Frictional Forces on Collar Bearings, Pivot

Bearings, and Disks 429

8.7 Frictional Forces on Journal Bearings 432

8.8 Rolling Resistance 434

**9 Center of Gravity andCentroid 447**

Chapter Objectives 447

9.1 Center of Gravity, Center of Mass, and the

Centroid of a Body 447

9.2 Composite Bodies 470

9.3 Theorems of Pappus and Guldinus 484

9.4 Resultant of a General Distributed

Loading 493

9.5 Fluid Pressure 494

**10 Moments of Inertia 511**

Chapter Objectives 511

10.1 Definition of Moments of Inertia

for Areas 511

10.2 Parallel-Axis Theorem for an Area 512

10.3 Radius of Gyration of an Area 513

10.4 Moments of Inertia for

Composite Areas 522

10.5 Product of Inertia for an Area 530

10.6 Moments of Inertia for an Area about

Inclined Axes 534

10.7 Mohr’s Circle for Moments of Inertia 537

10.8 Mass Moment of Inertia 545

**11 Virtual Work 563**

Chapter Objectives 563

11.1 Definition of Work 563

11.2 Principle of Virtual Work 565

11.3 Principle of Virtual Work for a System of

Connected Rigid Bodies 567

11.4 Conservative Forces 579

11.5 Potential Energy 580

11.6 Potential-Energy Criterion for

Equilibrium 582

11.7 Stability of Equilibrium Configuration 583

Appendix

A. Mathematical Review and

Expressions 598

Fundamental Problems

Partial Solutions and

Answers 603

Answers to Selected

Problems 620

Index 650