LECTURE 16
Internal Forces
Internal Loading
To design a structural or mechanical member, it is
necessary to know the loading acting within the member
in order to be sure that the material can resist this loading.
Internal loading can be determined by us

LECTURE 4
Force Vector
Addition of a System of Coplanar Forces
Scalar Notation
When a force is resolved into two components
along the x and axes, the components are then
called rectangular components.
Because these components form a right triangle,
the

LECTURE 3
Force Vector
Scalars and Vectors
All physical quantities in engineering mechanics are
measured using scalars or vectors.
Scalar any positive or negative physical quantity that
can be completely specified by its magnitude.
Length, mass, and ti

LECTURE 6
Equilibrium of a Particle.
Condition for the Equilibrium of a Particle
Particle equilibrium remain at rest if originally at rest or
has a constant velocity if originally in motion.
Static equilibrium describe an object at rest.
To maintain eq

LECTURE 5
Position Vector
X, Y, Z Coordinates
Throughout the book, we
will use a right handed
coordinate system to
reference the location of
points in space.
What is the coordinate
point of A and B?
Position Vector
A position vector r is define as a fi

LECTURE 8
Force System Resultants
Moment of Force
Moment of Force
Moment of Force
The magnitude Mo:
Mo = F x d
Where d is the moment arm or perpendicular distance from the
axis at point O to the line of action of the force.
Units of moment: N.m (SI Un

LECTURE 9
Force and Couple System
Moment of Couple
Two parallel forces that have the same magnitude, but
opposite directions, separated by a perpendicular
distance, d.
Since the resultant force is zero, the only effect of a
couple is to produce an actua

LECTURE 10
Reduction of a Simple Distributed Loading
Reduction of a Simple Distributed Loading
Sometime, a body may be subjected to a loading that is
distributed over its surface.
Pa or N/m2
lb/ft2
(SI UNIT)
(US Customary System)
Magnitude of Resultan

LECTURE 7
Three Dimensional Force System
Three- Dimensional Force Systems
For particle equilibrium, ALL forces
must be sum to produce zero force
resultant (F = 0).
In the case of three-dimensional force
system:
Fx = 0
Fy = 0
Fz = 0
Using them, we ca

LECTURE 11
Equilibrium of Rigid Body
Equilibrium of Rigid Body
Equilibrium of Rigid Body
Previous chapter:
The forces and couple moment system acting on a body can be
reduced to an equivalent resultant force and resultant couple
moment at any arbitrary

LECTURE 12
Equilibrium in Three Dimensions
Equilibrium in Three Dimensions
The first step in solving three-dimensional equilibrium problems is to
draw free body diagram recognize the type of supports.
Please Look at Table 5-2 on page 238 239 for more Ty

LECTURE 15
Frames and Machines
Frames and Machines
Frames and machines are 2 types of structures which are often
composed of pin-connected multi-force members members
that are subjected to more than 2 forces.
Frames support loads.
Machines contain movi

LECTURE 13
Structural Analysis
Simple Truss
Truss structure composed of slender members joined
together at their end points.
Planar trusses lie in a single plane and are often used to
support roofs and bridges.
Simple Truss
To design the members and th

LECTURE 14
The Method of Sections
Method of Sections
When we need to find the
force in only a few members
of a truss, we can analyze
the truss using the method
of sections.
However, it has to be based
on the principle that if the
truss is in equilibrium

CHAPTER 1
General Principles
Topic Overview
General Principles.
Force Vectors.
Equilibrium of a particle.
Force System Resultant.
Equilibrium of Rigid Body.
Structural Analysis.
Internal Force.
Friction.
Center of Gravity.
Moment of Inertia.
Obj