JJ205: ENGINEERING MECHANICS COURSE INTRODUCTION Course Lecturer:Mohd Noordin bin Ibrahim Room : JKM 1 Tel. No. : /

Course Textbook and Lecture Times REFERENCES Vector Mechanics For Engineers By F.P. Beer and E.R. Johnston (Third Metric Edition), McGraw-Hill. Ferdinand, P. B. and Russell Johnston, Jr. (1987). Mechanics for Engineers- Dynamics, McGraw Hill International Editions. ISBN Hibbeler,R.C (2004). Engineering Mechanics: Statics 3rd SI Edition.Pearson Prentice Hall, Singapore

Lesson learning outcome (LLO) At the end of this lesson, student should be able to; Define the concepts of mechanics List the basic measurement quantities Describe Newton’s Laws of motion CHAPTER ONE: BASICS CONCEPTS OF STATICS

What is Mechanics Deals with the Study and Prediction of the State of Rest or Motion of Particles and Bodies under the action of Forces

1.1 Concept of mechanics Statics - Deals With the Equilibrium of Bodies, Either at Rest or Move With a Constant Velocity. Dynamics -Concerned With the Accelerated Motion of Bodies. Space - the geometric region occupied by bodies whose positions are described by linear and angular measurements relative to a coordinate system.

Particle – a body which has mass but negligible dimension. Rigid body - a body is considered rigid when the relative movement between its parts are negligible

1.2 Basic measurement quantities Length – the measurement or extent of something from end to end. Basic unit for length is meter (m). It is the length of the path travelled by light in vacuum during a time interval of 1/ of a second. Time - the measure of the succession of events Basic unit for time is second (s). Mass - the measure of the inertia of a body, which is its resistance to a change of motion. sometimes called "quantity of matter“. Basic unit for mass is gram (g). Force - the action of one body on another (N)

1.3 Newton's Laws of motion Introduction Sir Isaac Newton was one of the greatest scientists and mathematicians that ever lived. He was born in England on December 25, Newton had new ideas about motion, which he called his three laws of motion. He also had ideas about gravity, the diffraction of light, and forces.

1.Newton's first law of motion (law of inertia) A particle remains at rest or continues to move in a straight line with a constant speed if there is no unbalanced force acting on it (resultant force = 0). or An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

2.Newton's second law of motion the acceleration of a particle is proportional to the resultant force acting on it and is in the direction of this force. (F = ma) or Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).

What does this mean? Everyone unconsiously knows the Second Law. Everyone knows that heavier objects require more force to move the same distance as lighter objects.

3. Newton's third law of motion

THANK YOU

1. Who was the scientist who gave us the Laws of Motion? 2. How many Laws of Motion are there? 3. What is another name for the first law of motion? 4. Which law explains why we need to wear seatbelts? 5. Which law says that force is equal to mass times acceleration (F=MA)? 6. Which law says that heavier objects require more force than lighter objects to move or accelerate them? 7. Which law explains how rockets are launched into space? 8. Which law says that for every action there is an equal and opposite reaction?

1. Who was the scientist who gave us the Laws of Motion? Answer: Sir Isaac Newton 2. How many Laws of Motion are there? Answer: three 3. What is another name for the first law of motion? Answer: Law of Inertia 4. Which law explains why we need to wear seat belts? Answer: First Law of Motion 5. Which law says that force is equal to mass times acceleration (F=MA)? Answer: Second Law of Motion 6. Which law says that heavier objects require more force than lighter objects to move or accelerate them? Answer: Second Law of Motion 7. Which law explains how rockets are launched into space? Answer: Third Law of Motion 8. Which law says that for every action there is an equal and opposite reaction? Answer: Third Law of Motion