The document provides an introduction to engineering mechanics, outlining the differences between engineering and science, and presents course objectives such as understanding systems of units and classifications of mechanics. It details scalar and vector quantities, as well as the principles of engineering mechanics grounded in Newton's laws and other fundamental principles. Key concepts include the definition of mechanics, the significance of units, and the application of forces leading to motion or rest.

1. 1
Module-1: Introduction to engineering mechanics
Learning outcomes:
Describe what makes engineering different from science
course overview
Identify the systems of units used in the course
Classification of mechanics
Scalars and Vectors
Principles of engineering mechanics

2. 2
“The scientist discover the world that exists.
The engineer creates what never was.”
An engineer uses scientific principles to design and operate
equipment, to move and interact materials
Scientist vs Engineer

3. 3
course overview

4. 4
Identify the systems of units used in the course
Parameter SI (metric)
Distance Meters (m)
Velocity Meters/sec (m/s)
Acceleration Meters/sec2 (m/s2)
Mass Kilogram (kg)
Force Newton (N) = kg*m/s2
Energy Joules (J) = N-m
Multiplier Prefix Symbol
109 giga G
106 mega M
103 Kilo K
10-2 Centi c
10-3 milli m
10-6 micro μ
10-9 nano n
10-12 pico p

5. MEchanics
5
Classification of mechanics
Mechanics
Mechanics of
solids
Mechanics of
rigid bodies
Statics Dynamics
Kinematics Kinetics
Mechanics of
deformable
bodies
Mechanics of
fluids
1.Ideal fluid
2.Viscous fluid
3.Incompressible fluid
“Mechanics can be defined as
that science which describes
and predicts the condition of
rest or motion of bodies under
the action of forces”

6. 6
Scalars and Vectors
Scalar Quantity
Has magnitude
Has no associated direction
Examples:
Volume Time
Mass distance
Speed Density
Temperature
Vector Quantity
Has magnitude
Has direction
Examples:
Moment Displacement
Velocity Acceleration
Force

7. 7
Distance vs Displacement:
Suppose you are observing an ant on the table, as
shown in the diagram below. The ant moves from one
corner of the table to the other corner. The blue
irregular line shows the path of the ant (distance) and
green straight line is the shortest path (displacement).
Scalars and Vectors

8. 8
Principles of engineering mechanics
Sir Isaac Newton - 25 December
1642 – 20 March 1727
was an English physicist and
mathematician (described in his
own day as a "natural philosopher")
who is widely recognised as one of
the most influential scientists of all
time and as a key figure in the
scientific revolution.

9. 9
Principles of engineering mechanics
Newton’s first law:
“An object at rest stays at rest and an object in motion stays in motion with the same
speed and in the same direction unless acted upon by an unbalanced force. This law
is often called the law of inertia.”
Example :The motion of a kite when the wind changes can also be described by the
first law

10. 10
Principles of engineering mechanics
Newton’s second law:
The rate of change of momentum is
directly proportional to impressed
force and it takes place in the
direction of force acting on it”.
Force ∝ rate of change of momentum.
But momentum = mass × velocity
As mass do not change
Force ∝ mass × rate of change of velocity
i.e., Force ∝ mass × acceleration
F ∝ m × a

11. 11
Principles of engineering mechanics
Newtons’s third law:
“For every action there is an equal and opposite reaction”.

12. 12
Principles of engineering mechanics
Newton’s law of gravitation:
“Everybody attracts the other body. The force of attraction between any
two bodies is directly proportional to their masses and inversely
proportional to the square of the distance between them”
Where G=6.67*10-11 N-m2/kg2

13. 13
Principles of engineering mechanics
Principle of transmissibility:
“The state of rest or of Uniform motion of
a rigid body is unaltered if the point of
application of the force is transmitted to
any other point along the line of action of
the force”.

14. 14