# Engineering Mechanics: Statics

## Introduction/Purpose

The first edition of this text was published in 1993 by John Wiley & Sons, Inc. The second edition was published in 1996. Our purpose in writing this Statics book, together with the companion Dynamics book, was to present a fresh look at the subject and to provide a more logical order of presentation of the subject material (particularly in the companion Dynamics book). We believe that our order of presentation will give students a greater understanding of the material and will better prepare students for future courses and later professional life.

## Organization

This volume on Statics is divided into 11 chapters. The first six chapters are used to develop fundamental concepts and the principle of equilibrium. The principle of equilibrium is then applied to a wide variety of problems in Chapters 7, 8, and 9. Second moments of area and moments of inertia are developed in Chapter 10. The method of virtual work and the principle of potential energy are developed in Chapter 11.

It is assumed that students have some background in vectors and vector algebra, and Chapter 2 develops the concepts of forces, components, and resultants using this vector background. A brief review of vectors and vector algebra is included in Appendix A for those students who need it. In Chapter 3 students are introduced to free-body diagrams and solve particle equilibrium problems. Solving some simple equilibrium problems before developing the more complicated vector principles in Chapter 4 gives students an appreciation for why they are studying the material and helps keep students interested in the course.

Center of gravity and the related topics of center of mass and centroid are developed in Chapter 5. These concepts are then used in the development of resultants of distributed force systems. Not only is the coverage of these concepts a natural extension of the concepts of equivalent force-couple systems and resultants which are developed in Chapter 4, but also, this early coverage allows the use of distributed forces in rigid body equilibrium problems in the rest of the book.

## Engineering Emphasis

Throughout this book, strong emphasis has been placed on the engineering significance of the subject area in addition to the mathematical methods of analysis. Many illustrative example problems have been integrated into the main body of the text at points where the presentation of a method can be best reinforced by the immediate illustration of the method. Students are usually more enthusiastic about a subject if they can see and appreciate its value as they proceed into the subject.

We believe that students can progress in a mechanics course only by understanding the physical and mathematical principles jointly, not by mere memorization of formulas and substitution of data to obtain answers to simple problems. Furthermore, we think that it is better to teach a few fundamental principles for solving problems than to teach a large number of special cases and trick procedures. Therefore, the text aims to develop in the student the ability to analyze a given problem in a simple and logical manner and to apply a few fundamental, well-understood principles to its solution.

A conscientious effort has been made to present the material in a simple and direct manner, with the student's point of view constantly in mind. Clarity is never sacrificed for the sake of mathematical elegance. Calculus and vector algebra are used wherever it provides an efficient solution to a problem. However, if formal vector algebra offers no advantage, then a scalar or geometric-vector approach is used instead. Likewise, students are encouraged to develop the ability to select the mathematical tools most appropriate for the particular problem they are attempting to solve.

## Sample Syllabi

Because we have been asked, we make available the following abbreviated syllabi for courses using our Statics and Dynamics texts. The following pointers are to 20-hour (2 quarter credit), 30-hour (3 quarter credit or 2 semester credit), 40-hour (4 quarter credit), and 45-hour (3 semester credit) variants of the Statics syllabus as well as a 75-hour variant of a combined Statics/Dynamics syllabus.

These syllabi are purposely vague and obviously are only a few of the many variations possible. More detailed syllabi will depend on whether the courses are intended primarily for civil engineering students or for mechanical engineering students; on whether the courses are primarily taken by freshman students or sophomore students; on whether the students will be taking additional mechanics courses or not; etc.

However, we hope that these brief outlines will be useful to instructors as you make up your syllabi.

An abbreviated syllabus for a 2 quarter credit Statics course. (Note that this abbreviated syllabus presumes that the student will have significant prior exposure to vector manipulation as well as coverage of centroid/center of gravity calculations in Mathematics and/or Physics. )

An abbreviated syllabus for a 3 quarter credit or a 2 semester credit Statics course.

An abbreviated syllabus for a 4 quarter credit Statics course.

An abbreviated syllabus for a 3 semester credit Statics course.

An abbreviated syllabus for a 5 semester credit Combined Statics and Dynamics course.

Comments and suggestions should be sent to:
 sturges@iastate.edu Leroy D. Sturges 2019 Black Engineering Iowa State University Ames, Iowa 50011-2162 515-294-6242

©1998, Leroy D. Sturges (revised 3 August 1998)