Hey guys, our first topic for today is Engineering Mechanics
which is the basic concept of every subject that you will study
in your higher year in civil engineering course
so under in Engineering Mechanics, we will study here our concept
first concept of Engineering Mechanics is
is the Rigid Bodies, so if we say rigid body
the definite amount of matter (and if we say matter...
is anything that has mass and volume), where this matter, or any
small elements of that matter is fixed on
each other.
Another concept is Force.
personally I think forces it is anything
that tends to change or that cause
changes on that rigid bodies. If we say changes,
means in terms of its motion or movement
and in terms of its formation
so if we say that these rigid bodies move,
our study for those rigid bodies is for "dynamics",
and if we say that these forces act in these rigid bodies
and remain at rest, this is what we call "statics".
And those are the two parts for engineering mechanics (statics & dynamics)
First part is Statics, here we study the effect of forces
on rigid bodies and that body will
remain at rest,
meaning there is no motion or there
is no movement on that certain body
meanwhile in Dynamics, we study
the effect and distribution of force where it caused movements in rigid body.
So we will study first Statics
and all rigid bodies to be analyzed here in this part
and solved will remain at rest.
Under Statics of Rigid Bodies, we study
force system. There are two types of
forces system according to the plane
Coplanar, and Non-coplanar
If we say Coplanar Force System, all forces
on a certain body lies in one plane. For example this is the plane
and all forces lie in this plane only,
and that's what we call Coplanar Force System
And if we say Non-Coplanar Force System,
forces act or lie in two or more planes.
For example this is the second plane
and forces act and lie in this 2nd plane
and this is the difference between Coplanar and Non-coplanar Force System.
These two type of force system were based
according to the plane
where forces acted upon.
The 2nd type of force system
is according to the line of action
and that's what we call Concurrent Force System
and Non-concurrent force System
and lastly, the Parallel Force System.
So these three is the type of force system according to the line of action
and these three is under coplanar force system
If we say Concurrent Force System, all forces
lie only in one point
Example we have point A
and all forces will intersect at a common point.
The line of action of this force is horizontal
while the line of action of this inclince force
is also going to intersect at A
while this force is directed away from point A
but still, the line of action of this force intersects at A.
So that is concurrent force system.
If we say Non-concurrent force system, all forces
originates or coming from different point
For example this is point A, point B and point C.
So the line of action of this force only acts in point A
and this force intersects only at point B
and this force at point C.
So that is Non-concurrent Force System.
And if we say Parallel Force System, all forces
are parallel to each other, so for example we have a vertical force here
upward vertical force great so this is
parallel forces
and there can be an inclined forces but still can be a parallel forces
as long as they're parallel to each other or
there's a distance between them and that
distance is perpendicular for that two forces
then we can consider that those forces are parallel to each other.
Next important thing in engineering mechanics
and used during analysis
is what we call the "Free-Body Diagram" or FBD.
So if we say Free-Body Diagram, we isolate
the parts/members on a certain body
and every parts (FBD), we can solve forces and apply forces
and we can solve internal forces sa certain FBD
and we can apply the FBD
under Chapter III of Engineering Mechanics
So that is Chapter I for the Introduction of Engineering Mechanics
So thank you for watching. Bye bye! :)
