CIVE 1150 Fall 2008

College of Engineering

Engineering Mechanics: StaticsCIVE-1150 Sec. 1 – 6 & 91

Omar Abu-Yasein, PhD., P.E., SECB omar@aa-engineers.com

CIVE 1150 Fall 2008

College of Engineering

Overview of SyllabusTeaching Philosophy: I enjoy teaching this class. This class is

fundamental to your success in any course which involves solids or fluids. My basic perspective is that of Herodotus: “The teacher has not taught, unless the student has learned”. I expect to help you be successful in this class and for you to leave this class well prepared to succeed in dynamics and strength of materials and subsequently machine design, structural analysis or biomechanics courses.

CIVE 1150 Fall 2008

College of Engineering

Overview of Syllabus Prerequisites: Math 1850: Calculus I, Physics 2130: Physics

I Text: Vector Mechanics for Engineers: Statics,

Eighth Edition, F.P. Beer, E.R. Johnston , McGraw-Hill, 2007.

Office Hours TA Instructor

Web CtIs McGraw-Hill website of any use?Honors

CIVE 1150 Fall 2008

College of Engineering

Conduct of the Course:Three hours per week including lectures, discussions, and problem sessions. Solve lots of problemsThere are reading assignments, homework problems, quizzes, two midterm exams and a final examination. There will be a great deal of hands on and observed problem solving in the class. History has shown Regular attendance is necessary to be successful in the class. Quizzes will be short (12 minutes) at the end of class.

CIVE 1150 Fall 2008

College of EngineeringGrading:

There is no grading curve in the course. You are not competing against the other students. You will receive whatever grade you meet the standard for regardless of how many other students have that grade.

Weighting Grading Scale Homework & Quizzes

20% A 93+ B+ 87-89 C+ 75-79 D+ 63-66 F < 57

2 Midterms @25%

50% A- 90-92 B 83-86 C 70-74 D 60-62

Final 30% B- 80-82 C- 67-69 D- 57-59 100%

CIVE 1150 Fall 2008

College of Engineering

Goals:At the end of this course, you will be able

to demonstrate by examination that you canDraw free body diagramsWrite and solve equilibrium equations for particles and rigid bodiesFind internal and external reactions for rigid bodiesFind centroids and moments of inertia for plane figuresDraw shear and bending moment diagrams for statically determinate structures. Present solutions to simple engineering problems in a professional mannerKeep track of units in the problems

Test the reasonableness of your answers. 

CIVE 1150 Fall 2008

College of Engineering

Goals:Students will be successful. This

means1) If you are at the beginning of the mechanics

sequence, you will understand the material, get a good grade in this course and be well prepared for strength of materials.

2) If you are taking this course to prepare for the FE, you will gain enough understanding to be successful on the statics part of the Fe and get a good grade.

CIVE 1150 Fall 2008

College of Engineering

ValuesMake changes to benefit mankind.Independent thinkerCreativeBe sure your solution is reasonableProduce work that can be checked

CIVE 1150 Fall 2008

College of Engineering

Ch. 1 Intro. What is Mechanics?Mechanics is a physical science which deals with bodies at rest or motion under the action of forces.Mechanics is an applied science - it is not an abstract or pure science.Mechanics is the foundation of most engineering sciences.Categories of Mechanics: Rigid bodies- Statics or Dynamics Deformable bodies Fluids

CIVE 1150 Fall 2008

College of Engineering

Fundamental ConceptsSpace - associated with the notion of the position of a point P given in terms of three coordinates measured from a reference point or origin. Time - definition of an event requires specification of the time and position at which it occurred.

Mass - used to characterize and compare bodies, e.g., response to earth’s gravitational attraction and resistance to changes in translational motion.

Force - represents the action of one body on another. A force is characterized by its point of application, magnitude, and direction, i.e., a force is a vector quantity.In Newtonian Mechanics, space, time, and mass are absolute concepts, independent of each other. Force, however, is not independent of the other three. The force acting on a body is related to the mass of the body and the variation of its velocity with time.

CIVE 1150 Fall 2008

College of Engineering

Six Fundamental Principles

• Parallelogram Law

• Principle of Transmissibility

• Newton’s First Law: If the resultant force on a particle is zero, the particle will remain at rest or continue to move in a straight line.

• Newton’s Third Law: The forces of action and reaction between two particles have the same magnitude and line of action with opposite sense.

• Newton’s Second Law: A particle will have an acceleration proportional to a nonzero resultant applied force.

amF

• Newton’s Law of Gravitation: Two particles are attracted with equal and opposite forces,

22,

R

GMgmgW

r

MmGF

CIVE 1150 Fall 2008

College of Engineering

Systems of Units

• Kinetic Units: length, time, mass, and force.

• Three of the kinetic units, referred to as basic units, may be defined arbitrarily. The fourth unit, referred to as a derived unit, must have a definition compatible with Newton’s 2nd Law,

amF

• International System of Units (SI):The basic units are length, time, and mass which are arbitrarily defined as the meter (m), second (s), and kilogram (kg). Force is the derived unit,

2s

m1kg1N1

maF

• U.S. Customary Units:The basic units are length, time, and force which are arbitrarily defined as the foot (ft), second (s), and pound (lb). Mass is the derived unit,

sft1

lb1slug1

a

Fm

CIVE 1150 Fall 2008

College of Engineering

Method of Problem Solution

• Problem Statement: Includes given data, specification of what is to be determined, and a figure showing all quantities involved.

• Free-Body Diagrams:Create separate diagrams for each of the bodies involved with a clear indication of all forces acting on each body. This is tough.

• Fundamental Principles:The six fundamental principles are applied to express the conditions of rest or motion of each body. The rules of algebra are applied to solve the equations for the unknown quantities.

• Solution Check: - Test for errors in reasoning by verifying that the units of the computed results are correct,- test for errors in computation by

substituting given data and computed results into previously unused equations based on the six principles,- always apply experience and physical intuition to assess whether results seem “reasonable”

CIVE 1150 Fall 2008

College of Engineering

Numerical Accuracy

• The accuracy of a solution depends on 1) accuracy of the given data, and 2) accuracy of the computations performed. The solution cannot be more accurate than the less accurate of these two.

• As a general rule for engineering problems, the data are seldom known with an accuracy greater than 0.2%. Therefore, it is usually appropriate to record parameters beginning with “1” with four digits and with three digits in all other cases, i.e., 40.2 lb and 15.58 lb.

• The use of hand calculators and computers generally makes the accuracy of the computations much greater than the accuracy of the data. Hence, the solution accuracy is usually limited by the data accuracy.