The document provides an introduction to the topic of applied mechanics. It defines mechanics as a branch of science dealing with bodies at rest or in motion under the influence of forces. Mechanics is divided into statics, dynamics, and the mechanics of rigid bodies, deformable bodies, fluids, and their compressible and incompressible types. Fundamental concepts such as particles, bodies, rigid bodies, deformable bodies, space, time, force, and systems of units are also defined. Several fundamental principles are outlined, including Newton's laws of motion and the laws of gravitation, the parallelogram of forces, and Lami's theorem. Finally, the document instructs students to form groups of five and design a simple
2. What is Mechanics?
Mechanics is a branch of
science which deals with
bodies at rest or motion
under the action of
forces.
3. Structure of Mechanics
Mechanics
Applied Mechanics
(Mechanics applied to
Engg. Problem)
Mechanics of Rigid Bodies Mechanics of Deformable
(Things that do not change Bodies Mechanics of Fluids
shape) (Things that do change shape)
Statics Dynamics Incompressible Compressible
Kinetics Kinematics
(Forces which causes the (Forces which causes the motion
motion are considered) are not considered)
4. Fundamental Concepts
Particle- it is an idealized body which may have negligible
mass and whose size and shape can be neglected
Matter- substances that posses weight, occupies space,
volume, apprehended by sense.
Body: the matter bounded by a closed surface is called
body.
It is accumulation of large number of particles
Rigid Body- if the relative distance between the particle of
the body is same before and after the application of forces.
Deformable body: if the relative distance between the
particle of the body is different(change) before and after the
application of forces.
6. Space - associated with the notion of the position of a point P
given in terms of three coordinates measured from a reference
point or origin.
OR
The unlimited expanse of physical dimensions in which all
material objects are located
Time- It is a measure of duration between successive events.
Force - Represents the action of one body on another.
A force is characterized by its point of application, magnitude,
and direction.
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. Systems of Unit
FPS: Foot, Pound, Second
CGS: Centimeter, Gram, and Second
MKS: Metre, Kilogram and second
SI: System International
8. Fundamental Units
Physical Unit
Symbol Unit
Quantity symbol
length l metre m
mass m kilogram kg
time t second s
electric current I ampere A
thermodynamic
T kelvin K
temperature
amount of
n mole mol
substance
9. Prefix of SI system
Sr. Prefix Symbol Expontial
No. Notation
1 Exa E 1018
2 Peta P 1015
3 Tera T 1012
4 Giga G 109
5 Mega M 106
6 Kilo K 103
7 Hecto h 102
8 Deka da 101
9 Deci d 10-1
10 Centi c 10-2
12 Milli m 10-3
13 Micro 10-6
14 Nano n 10-9
15 pico p 10-12
10. Derived Units
Physical Unit Unit Symbol
Quantity
Acceleration metre/second2 m/s2
Angular Velocity radian/second rad/s
Angular radian/second2 rad/s2
acceleration
Force Newton N or kgm/s2
Moment of Force Newton metre Nm
Work, Energy Joule J or Nm
Torque Newton metre Nm
Power Watt W= J/s2
Pressure Pascal Pa = N/m2
Frequency Hertz Hz or 1/s
12. 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.
13. • Newton’s Second Law: A particle will have an
acceleration proportional to a nonzero resultant applied
force.
• When a force acts on an object, the object accelerates in
the direction of the force.
• If the mass of an object is held constant, increasing force
will increase acceleration.
• If the force on an object remains constant, increasing mass
will decrease acceleration.
14.
15.
16. Newton’s Third Law: The forces of action and reaction
between two particles have the same magnitude and line of
action with opposite sense.
17.
18. Newton’s Law of Gravitation: Two particles are attracted with
equal and opposite forces.
•every point mass in the universe
attracts every other point mass with a
force that is directly proportional to
the product of their masses and
inversely proportional to the square of
the distance between them.
GM
W = mg g = G = 6.67 x 10-11 Nm2/kg2
R2
19. Law of Parallelogram of Forces
If the two forces acting at a point be represented in
magnitude and direction by the two adjacent sides of
a parallelogram, then their resultant is represented in
magnitude and direction by the diagonal of the
parallelogram passing through that point.
The magnitude of Resultant force R
• Parallelogram Law
20. Law of Triangle of forces
“If the forces acting at a point be represented
in magnitude and direction by the three sides
of a triangle taken in order, they will be in
equilibrium.”
21. Lami’s Theorem:
if three forces acting at a fixed point
are in equilibrium, each force will be
proportional to the sine of the angle
between the other two forces.”
22. Principle of Transmissibility
Conditions of equilibrium or motion are not affected by
transmitting a force along its line of action.
F and F’ are equivalent forces.
23. Task
Draw one simple mechanism to lift
the body or water or weight.
Make the group of five students.