Concept of Applied Mechanics

 

CONCEPT AND EXPLANATION OF MECHANICS AND APPLIED MECHANICS:

• Mechanics is the branch of science which deals with the study of forces on bodies and motion of a physical system.

• Mechanics deals with the behavior of forces and their effects on different bodies.

• This subject affects our day to day life like the use of balance, use of iron rod to move heavy object, motion of vehicle etc.

• Applied Mechanics is the branch of engineering which deals with the study of actual application of principles of mechanics to solve practical engineering problems.

Everything around us including buildings, machinery, electric poles, vehicles etc. is designed by using the principles of mechanics. Some of the important applications of principles of mechanics in daily life are: motion of vehicles, trains, flight of airplanes and projectiles, stresses in bridges and trusses, forces on columns and walls in buildings, buoyant forces in water and air etc.

IMPORTANCE AND NECESSITY:

• The knowledge of this subject enables an engineer to properly design all types of structures and machines. Thus it is very essential to study the various law of applied mechanics to determine the various forces acting in a frame structure, flight of an airplane and projectiles etc., so as to execute the design and construction in the engineering field.

 

BRANCHES OF APPLIED MECHANICS:

Applied Mechanics is broadly divided into two branches:
(1) Statics                                                    (2) Dynamics

 

(a) Statics:

It is the branch of applied mechanics which deals with the study of forces acting on a physical system at rest(in equilibrium). All such bodies which are acted upon by the external forces but are either at rest or in uniform motion come under the scope of statics. 

Example: Study of different types of forces acting on a bench kept in a classroom.

 

(b) Dynamics:
It is the branch of applied mechanics which deals with the action of forces on bodies in motion.

Example: Study of different types of forces acting on a car moving on a road.

 

Dynamics is further subdivided in two parts:
(i) Kinetics                                                  (ii) Kinematics

(i) Kinetics:
It is the branch of dynamics which deals with the study if forces responsible for motion of a body and the sources of these forces.

Example: Study of forces causing acceleration and retardation of bodies comes under the scope of kinetics.

 

(ii) Kinematics:
It is the branch of dynamics which deals with the study of motion of bodies without any reference to the forces causing the motion.

Example: Freely falling bodies under gravity, relative velocities of boat and river.

 

CONCEPT OF RIGID BODIES:

A rigid body is a body which does not change its shape and size under the action a forces or in other words, a rigid body does not undergo any deformation due to application of external forces.

In mechanics we assume that all bodies are rigid bodies but actually no body is found to be perfectly rigid. However, most of the bodies are elastic over a wide range of forces. The changes in their dimensions disappear after the removal of the forces and original shape and size is regained in short-time. But this does not affect the study of forces and motion of a body to greater extent. Since general principles applied to rigid bodies and elastic bodies are identical, it is safe to assume, all bodies to be rigid bodies for the purpose of applied mechanics.

 

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