1. What is statics? Lecture 1
Branch of physical sciences concerned with the state of rest or motion of bodies subjected to forces is called Mechanics.
The following diagram shows that Statics stands under solid mechanics of rigid bodies.
Rigid body: A combination of a large number of particles which remain in a fixed position relative to each other, both before and after the application of a force. A body is considered rigid when the changes in distance between any two points within its body are negligible
Deformable body: A body is considered deformable when the changes in distance between any two of its points cannot be neglected.

2. Lecture 1
What is statics?
Statics is actually the application of mathematics and basic physics (Newton’s laws) to study forces in materials, machines and structures. 
Forces are of interest to engineers for two reasons:
They cause materials to deform and break, and
They cause things to move. 
Statics is used to calculate forces in systems that don’t move, or move at constant velocity. 
The application of physics to study motion is known as dynamics.

3. What is Statics? Relation between forces and displacements
Lecture 1
What is Statics?
Relation between forces and displacements F x
Determine the components of a force in rectangular or nonrectangular coordinates.
Determine the resultant of a system of forces.
Draw complete and correct free-body diagrams and write the appropriate equilibrium equations from the free-body diagram.
Determine the support reactions on a structure.

4. What is Statics? Internal reaction: Friction:
Lecture 1
Internal reaction:
Determine the internal reactions in a beam,
Draw correct shear-force and bending moment diagrams, and
Write equations for the shear-force and bending moment as functions of position along the beam.
Friction:
Analyze systems that include frictional forces.

5. What is Statics? Trusses: Centroid: Moment of Inertia: Lecture 1
Determine the connection forces in trusses and in general frame structures.
Centroid:
Moment of Inertia:
Locate the centroid of an area.
(center of mass or center of gravity)
Calculate the mass moment of inertia, and the area moment of inertia.

6. Definitions
Lecture 1
Force:
Generally considered as a push or a pull exerted by one body on another. Interaction occurs when there is direct contact between the bodies. Gravitational, electrical and magnetic forces do not require direct contact.
Force is characterized by magnitude, direction and point of application.
Forces treated in mechanics as concentrated are in fact the resultants of corresponding systems of distributed forces.

7. Definitions Particle: Lecture 1
An object having mass but the size is neglected. = m
If rotational effects can be neglected for a particular body, then that body can be treated as a single particle with mass of the body concentrated at one point.
Examples:
The Earth might be considered a particle if we were studying its orbit around the Sun.
Travelled distance is too long compared to the car size, so the car treated as a particle.
A cannon ball shot through the air could be treated as a particle; the same ball rolled along the ground would have to be considered as a rigid body of a given radius.

8. Basic Dimensions and Unit of Mechanics
Lecture 1
Basic Dimensions and Unit of Mechanics
The dimensions that are independent of all other dimensions are termed primary or basic dimensions, and that which are developed in terms of the basic dimensions are called secondary dimensions.
The most convenient ones include the dimensions of length, time and mass [ MLT ]. The other units are described in terms of basic dimensions are termed the secondary dimensions.
Length:
It is a term or concept for describing size and dimensions of bodies or materials in space, without such measurement it can’t be acquiring a precise dimensions of them.
Thus, the other aspects of size, such as area and volume can be formulated in terms of the standard by the methods of plane and solid geometry. This standard is called a unit of the dimension length.
Many types of units are actually employed around the world; the most utilized types are the meter in SI unit and the foot in British unit.

9. Lecture 1
Mass:
Mass can be determined from two different actions of bodies. To study the first action, suppose we have two hard bodies of different size and shape … etc at the earth’s surface. If these bodies are attached to identical springs, each spring will extend some distance ( l1 and l2 ) as a result of the attraction of gravity for these bodies.
Now, if we stretch these two bodies downward an equal distance and release them at the same time, they will begin to move in an identical manner. If these bodies have same mass they will stretch to same extended distance.
So, the property of mass characterizes a body both in the action of gravitational attraction and in the response to a mechanical disturbance [ It is a measure of the inertia of a body, which is its resistance to a change of velocity ].
The unit of mass in SI system is the kilogram ( kg ) which is approximately equal to the mass of [ m3 ] of water, and in British unit the mass unit is the slug which is equal to 32.2 pound mass ( lbm ).

10. Time: Lecture 1 Secondary Dimensional Quantities Change of Units
The time defined as a concept of description, ordering or flow of events passed during our life. So, to define an event, it is not sufficient to indicate or mention its position in space, thus the Time of that event should also be given.
The rotation of the earth around itself serves as a good measure of time, but a smaller units is needed in engineering, this unit is generally the second which is an action repeatable 86,400 times a day [ 1 sec = 1/86,400 of a mean solar day ].
Secondary Dimensional Quantities
When physical acts or processes are described in terms of basic dimensions by the use of suitable definition [ for instance velocity is defined as a distance divided by the time interval ] these quantities are called secondary dimensional quantities.
Change of Units
To change units from one type to another that may be needed during computation of some mechanical problems, for instance we want to change the meter into foot or inch to centimeter. In such cases we must replace the unit in question by a physically equivalent number of the new units.
These must not be taken as algebraic relation but simply as indications of physical equivalences, and it can be written or expressed in another way:
The unity on the right side of these relations indicates that the numerator and denominator on the left side are physically equivalent and have ( 1 to 1 ) relation.

11. What you need to know from Physics! 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 the particle is not subjected to unbalanced forces.

12. Newton’s Three Laws of Motion
Second Law: A particle acted upon by an unbalanced force F experiences an acceleration that has the same direction as the force and a magnitude that is directly proportional to the force. m
If F is applied to a particle of mass m then: F = m. a

13. Newton’s Three Laws of Motion
Third Law: To every action there is always opposed an equal reaction , or the mutual forces of action and reaction between two particles are equal, opposite and collinear.

14. Newton’s Laws of Gravitational Attraction
The gravitational law of attraction states that, two particles (objects) will be attracted toward each other along their connecting line with a force whose magnitudes are proportional to the product of their masses and inversely proportional to the square distance between the particles.
Or, by inserting the constant of proportionality ( G ), and rearranging the above equation to yield:
Where:
F = force of gravitation,
G = universal constant of gravitation
G = × m3 kg-1 s-2
m1, m2 = masses of two particles,
r = distance between two particles.

15. Newton’s Laws of Gravitational Attraction
The relation between the earth with any of the bodies on the earth, it could be considered each of the earth and each of these bodies as a particle, its mass concentrated at its center of gravity, this action is called the weight of the particle on the earth’s surface.
According to this law, an object's weight is defined by:
                     
in which:
m = mass of object M = mass of earth r = distance from center of earth to particle
g = 9.81 m.s-2 (determined at sea level and at a latitude of 45o which is considered “standard location”).