ENGINEERING MECHANICS – INTRODUCTION
(a) Statics, and (b) Dynamics
The Statics is that branch of Engineering Mechanics which deals with the forces and their effects, while acting upon the bodies at rest.
The Dynamics is that branch of Engineering Mechanics which deals with the forces and their effects, while acting upon the bodies in motion. It is further sub-divided into the following two branches:
(i) Kinetics, and (ii) Kinematics
The Kinetics is that branch of Dynamics, which deals with the bodies in motion due to the application of forces.
The Kinematics is that branch of Dynamics which deals with the bodies in motion without taking into account the forces which are responsible for the motion.
FORCE - BASIC DEFINITION
Force may be defined
as an agent which produces or tends to produce, destroy or tends to destroy the
motion of a body. A force while acting on a body may
(a) change
the motion of a body,
(b) retard
the motion of a body,
(c) balance
the forces already acting on a body, and
(d) give
rise to the internal stresses in a body.
In order to determine the effects of a
force acting on a body, we must know the following characteristics of a force:
(i) The magnitude of the force,
(ii) The line of
action of the force,
(iii) The nature of
the force, i.e. push or pull, and
(iv) The point at
which the force is acting.
In M. K. S. system of units, the magnitude of the
force is expressed in kilogram-force (briefly written as kgf) and in S.I.
system of units, the force is expressed in newtons (briefly written as N). It
may be noted that
1 kgf =
9.81 N
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