ENGINEERING MECHANICS

                               CLASS 1

General Principles-

Mechanics- It is a branch of physical science that is concerned with the state of rest or motion of bodies that are subjected to the action of forces. In general, this subject can be subdivided into three branches-

1)Rigid body mechanics

2) Deformable body mechanics

3)Fluid mechanics

Rigid body mechanics is subdivided in two areas-

a)Statics- It deals with the equilibrium of bodies that are either at rest or move with constant velocity.

b) Dynamics- It is concerned with the accelerated motion of bodies.

Fundamental Concepts

1)Basic quantities

a)Length

b)Time

c)Mass

d)Force

2)Particle- A particle has a mass but a size that can be neglected.

For example, Earth can be modelled as a particle compared to its orbit.

3)Rigid Body- A rigid  body is combination of large number of particles in which all the particles remain at a fixed distance from one another both before and after applying load.

4) Newton's law of motion

a) 1st law- A particle originally at rest or moving in a straight line with constant velocity tends to remain in this state provided the particles in this state is not subjected to unbalanced force.

b)2nd law- A particle acted upon by an unbalanced force expression, an acceleration that has the same direction of force and a magnitude that is proportional to the force.

                                   F=ma

c)3rd law- For every action there is an equal and opposite reaction.