1. CHAPTER 1: INTRODUCTION & STATICS OF PARTICLES
STATICS AND DYNAMICS
PDT 101/3
CHAPTER 1: INTRODUCTION & STATICS OF PARTICLES
PREPARED BY:
Tan Soo Jin

2. CHAPTER OUTLINE Mechanics Fundamental Concepts Units of Measurement
The International System of Units

3. What Is Mechanics?
Study of what happens to a “thing” (the technical name is “BODY”) when FORCES are applied to it.
Either the body or the forces can be large or small.

4. 1.1 Mechanics
Mechanics is a branch of the physical sciences that is concerned with the state of rest or motion of bodies that are subjected to the action of forces.
Mechanics can be divided into 3 branches:
- Rigid-body Mechanics
- Deformable-body Mechanics
- Fluid Mechanics
Rigid-body Mechanics deals with
- Statics
- Dynamics

5. 1.1 Mechanics Statics – Equilibrium of bodies * At rest
* Move with constant velocity
Dynamics – Accelerated motion of bodies

6. 1.2 Fundamental Concepts Basic Quantities
Length - locate the position of a point in space
Mass - measure of a quantity of matter
Time - succession of events
Force - a “push” or “pull” exerted by one body on another
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.

7. 1.2 Fundamental Concepts Newton’s Three Laws of Motion First Law
“A particle originally at rest, or moving in a straight line with constant velocity, will remain in this state provided that the particle is not subjected to an unbalanced force”

8. 1.2 Fundamental Concepts F = ma Newton’s Three Laws of Motion
Second Law
“A particle acted upon by an unbalanced force F experiences an acceleration a that has the same direction as the force and a magnitude that is directly proportional to the force”
F = ma

9. 1.2 Fundamental Concepts Newton’s Three Laws of Motion Third Law
“The mutual forces of action and reaction between two particles are equal and, opposite and collinear”

10. 1.3 Units of Measurement SI Units
International System of units (worldwide recognition)
SI system specifies length in meters (m), time in seconds (s) and mass in kilograms (kg)
Force unit, Newton (N), is derived from
F = ma

11. 1.3 Units of Measurement

12. 1.3 Units of Measurement At the standard location,
gravitation (acceleration
of an object caused by the
force of gravity from another object)
g = m/s2
For calculations, we use
g = 9.81 m/s2
Thus,
W = mg (g = 9.81m/s2)
Hence, a body of mass 1 kg has a weight of 9.81 N, a 2 kg body weighs N

13. 1.4 The International System of Units
Prefixes
For a very large or small numerical quantity, units can be modified by using a prefix
Each represent a multiple or sub-multiple of a unit
Eg: 4,000,000 N = 4000 kN (kilo-newton)
= 4 MN (mega- newton)
0.005m = 5 mm (milli-meter)

14. 1.4 The International System of Units