Basic Lecture-1- Engineering Mechanics

Subject: Engineering Mechanics

Subject Code: ME 4301

Topic: Basic Lecture - lecture no-1

Lecturer: Md. Rezaul Karim

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Marks Distributions

Credits: 4

•Class attendance-10%

•Class Test-10%

•Assignment-10%

•Midterm-30%

•Final -40%

What is Mechanics?

•Mechanics is the study of bodies under the action of forces.

•Categories of Mechanics:

-Rigid bodies

-Statics–bodies at rest or at constant velocity

-Dynamics –accelerating bodies

-Deformable bodies

-Fluids –gas and/or liquid

•Mechanics is an applied science, closely related to physics, so many of the concepts will build on that prior knowledge.

•Mechanics is the foundation of many engineering topics and is an indispensable prerequisite to their study.

Fundamental Principles

• 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. am F= ma

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

Systems of Units

• 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,

F= ma

• 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,

F=ma

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.

•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,-alwaysapply experience and physical intuition to assess whether results seem “reasonable”

References

1.Ferdinand Beer, E. Russell Johnston Jr.: Vector Mechanics for Engineers (Statics and Dynamics)

2.Russell C. Hibbeler: Engineering Mechanics (Statics and Dynamics)

3.Lecture Notes :J. Walt Oler, Texas Tech University