Engineering Mechanics: Dynamics

Citation

Meriam, J. L., & Kraige, L. G. (2007). Engineering Mechanics: Dynamics (6th ed.). Wiley.

Chapter Summary

The sixth edition is the dynamics volume of the Meriam and Kraige Engineering Mechanics pair (the statics volume has its own ISBN). Its contents list eight chapters in two parts, followed by four appendices and an index. The publisher's description says the text has provided a foundation of mechanics principles for more than fifty years, that more than 40% of the homework problems are new in this edition, that there are new sample problems and more photographs linking theory to application, and that it strongly emphasises drawing free-body diagrams as the most important skill for solving mechanics problems.

Part I, Dynamics of Particles

The first four chapters, in order, are Introduction to Dynamics; Kinematics of Particles; Kinetics of Particles; and Kinetics of Systems of Particles. The split into kinematics (describing motion) and kinetics (relating motion to forces) is built into the chapter titles, and the part closes by extending particle kinetics to systems of particles.

Part II, Dynamics of Rigid Bodies

The next four chapters, in order, are Plane Kinematics of Rigid Bodies; Plane Kinetics of Rigid Bodies; Introduction to Three-Dimensional Dynamics of Rigid Bodies; and Vibration and Time Response. The part repeats the kinematics-then-kinetics pattern for bodies of finite size, first in the plane and then, as an introduction, in three dimensions, and ends with vibration and time response.

Appendices

Appendix A, Area Moments of Inertia; Appendix B, Mass Moments of Inertia; Appendix C, Selected Topics of Mathematics; and Appendix D, Useful Tables. The two inertia appendices collect area and mass moments of inertia in one place.

Key Concepts

Part I: particles

• Kinematics versus kinetics: describing motion on its own, and then connecting it to forces.
• Free-body diagrams: the skill the publisher says the book emphasises most strongly.
• Systems of particles: the extension of particle kinetics in the fourth chapter.

Part II: rigid bodies

• Plane motion of rigid bodies: kinematics and kinetics in two dimensions.
• Three-dimensional dynamics: the introduction that follows the plane chapters.
• Vibration and time response: the closing chapter.
• Moments of inertia: area and mass moments, in Appendices A and B.

Critical Analysis

Strengths

• A clear two-part architecture. Particles come first and rigid bodies second, each with kinematics before kinetics. The structure is visible from the contents alone, and a reader can see where each topic fits.
• Emphasis on problem-solving method. The publisher states that drawing free-body diagrams is strongly emphasised and that the book includes new sample problems, so the book supports learning by worked procedure.
• Refreshed problem set. More than 40% of the homework problems are new in this edition, according to the publisher, which matters to instructors who reuse problem sets across editions.
• Reference appendices. Area and mass moments of inertia, mathematical topics and useful tables are all in the volume, which keeps common reference material in the same volume.

Limitations

• Edition-specific problems. The 40% of new homework problems means problem numbers differ from earlier editions, so solution sets and syllabi written for another edition cannot be matched one to one.
• Introductory scope in places. Three-dimensional rigid-body dynamics is labelled an introduction in its chapter title, and vibration has a single closing chapter, so advanced work in either area needs other books.
• Dynamics only. Statics is in a separate volume, so a reader who needs equilibrium techniques must use another book.

Where It Fits in the Course

Meriam and Kraige is the dynamics textbook in the statics-and-dynamics list. It follows a statics course, and Hibbeler's Engineering Mechanics: Statics is the statics text on this list; the two books have different authors and publishers, so they are used together by choice rather than as a matched pair. Bird and Ross's Mechanical Engineering Principles covers statics, dynamics and basic strength of materials step by step from simple mathematics, and can serve as a gentler start. Moebs, Ling and Sanny's University Physics Volume 1 is the calculus-based physics background for kinematics, force and energy.

For further study, Williams's Fundamentals of Applied Dynamics develops particle and rigid-body dynamics, work-energy methods, momentum, vibrations and an introduction to Lagrangian analysis, and Rao's Mechanical Vibrations takes up free and forced vibration in depth, continuing from the vibration chapter.

How to Use This Book

The book is for engineering students taking a first dynamics course after statics. Calculus, vector algebra and a statics course are the natural preparation, since the free-body diagrams and force balances of statics are the starting point for kinetics.

A practical plan:

• Core: Part I in order. Make the free-body diagram a habit from the first kinetics chapter onward, because the publisher's emphasis shows it is the book's basic tool.
• Rigid bodies: Chapters 5 and 6 are the core of Part II; read the area and mass moments of inertia appendices when you need them.
• Optional: Chapter 7 (three-dimensional dynamics) and Chapter 8 (vibration), depending on the course.
• Practice: work the sample problems before the homework problems, and always start by drawing the free-body diagram.
• Pacing: a semester that covers Part I in the first half and the plane-motion chapters of Part II in the second half leaves the three-dimensional and vibration chapters for a follow-up course or for self-study.
• Checking work: state in words whether each problem is asking for motion from forces (kinetics) or motion from geometry (kinematics) before choosing equations; the chapter titles divide the book on exactly this line.
• Next steps: students who finish Part II and want more on vibration can go to Rao's Mechanical Vibrations, and those who want an analytical-mechanics view can go to Williams.