# MEEG 2003

Teaching Assistant, *University of Arkansas, Mechanical Engineering*, 2017

## Class Overview

**Summary:** Equilibrium and resultants of force systems in a plane and in space; analysis of structures, friction, centroids, moments of inertia, and virtual work method. Methods of analysis are emphasized.

**Corequisite:** MATH 2574 or MATH 2574C.

**Prerequisite:** PHYS 2054. (Typically offered: Fall, Spring and Summer)

## People

Instructor: Ing-Chang Jong | TA: Kashu Yamazaki |

## Lecture Information

**Text Book:** Jong, I. C., Engineering Mechanics: Statics, Second Edition, 2013, Great River Learning, Debuque, IA.

### Grades

9 collections of homework (each worth 5 points), 6 quizzes (each worth 10 points), 3 tests (each worth 100 points), n pop quizzes (each worth 5 pts), and a final exam (worth 100points). The total score you can possibly earn in this course may, therefore, be 505 + 5n points.

### Drill Sessions

**Time:** 6:30-8:30, Tuesdays

**Location:** BELL 2267

### Lecture Topics

**Test1**- 9/20 (Ch.1 ~ Ch.3)

**Summary:** Fundamental concepts/laws, addition and resolution of forces, equilibrium of particles, action to rotate a body, and moments with vector algebra

**Test2**- 10/30 (Ch.4 ~ Ch.6)

**Summary:** Equivalent and equipollent system, rigid-body equilibrium in a plane/space, POM, centroids and centers of gravity, areas/volumes, distributed loads, area moments of inertia, PAT, and trusses

**Test3**- 12/4 (Ch.6 ~ Ch.8)

**Summary:** Frames and machines, friction between rigid bodies, belt friction, work, displacement center, and virtual work

**Final Exam - 12/11 (Ch.1 ~ Ch.8)**

## Important Topics

### Principle of Moments (POM)

- Resultant = sum of components
- Moment of resultant = sum of moments of components

### Parallel-Axis Theorem (PAT)

The moment of inertia of a body about a given axis is related to the moment of inertia about a centroidal axis parallel to the given axis as follows:

### Work

**Work** is energy in transition to a system due to *force or moment* acting on the system through a displacement. Note that **Heat** is energy in transition to a system due to *temperature difference* between the system and its surroundings. Work differs from energy in that workis nota property possessed by a system, while energy (e.g., kinetic energy or potential energy) is. Work is a boundary phenomenon.

### Virtual Work Method

Three major steps for virtual work method:

- Draw the free-body (FBD) diagram.
- Draw the virtual-displacement diagram (VDD) with a strategy, which gives the free body a compatible virtual displacement in such a way that the one specified unknown, but no other unknowns, will be involved in the virtual work done.
- Set the total virtual work done to zero in order to solve for the unknown.

## Reference

- Jong, I. C., “Kindling Students’ Interest in Virtual Work Method: Advantages and Challenges,” Proceedings of the 2004 ASEE Midwest Section Conference, Pittsburg, Kansas, September 29 - October 1, 2004.
- Jong, I. C., “Teaching Students Work and Virtual Work Method in Statics: A Guiding Strategy with Illustrative Examples,” Proceedings of the 2005 ASEE Annual Conference & Exposition, Portland, Oregan, June 12-15, 2005.
- Jong, I. C., “From Conventional Method to Virtual Work Method in Statics: Three Major Steps and One Guiding Strategy,” Proceedings of the 2005 ASEE/AaeE 4th Global Colloquium, Star City, Sydney, Australia, September 26-29, 2005.
- Jong, I. C., “Learning the Virtual Work Method in Statics: What Is a Compatible Virtual Displacement?,” Proceedings of the 2006 ASEE Annual Conference & Exposition, Chicago, Illinois, June 18-21, 2006. (Also presented at the 5th ASEE Global Colloquium on Engineering Education, Rio de Janeiro, Brazil, October 8-12, 2006.)