# A Textbook of Engineering Mechanics

## A Textbook of Engineering Mechanics

R.S. KHURMI

Preference :

The subject of Engineering Mechanics is that branch of Applied Science, which deals with the
laws and principles of Mechanics, alongwith their applications to engineering problems. As a matter
of fact, knowledge of Engineering Mechanics is very essential for an engineer in planning, designing
and construction of his various types of structures and machines. In order to take up his job more
skilfully, an engineer must persue the study of Engineering Mechanics in a most systematic and
scientific manner.

BEGINNING AND DEVELOPMENT OF ENGINEERING MECHANICS
It will be interesting to know, as to how the early man had been curious to know about the
different processes going on the earth. In fact, he used to content himself, by holding gods responsible
for all the processes. For a long time, the man had been trying to improve his ways of working. The
first step, in this direction, was the discovery of a circular wheel, which led to the use of animal driven
carts. The study of ancient civilization of Babylonians, Egyptians, Greeks and Roman reveal the use
of water wheels and wind mills even during the pre-historic days.
It is believed that the word ‘Mechanics’ was coined by a Greek philosopher Aristotle
(384–322 BC). He used this word for the problems of lever and the concept of centre of gravity. At
that time, it included a few ideas, which were odd, unsystematic and based mostly on observations
containing incomplete information. The first mathematical concept of this subject was developed by
Archimedes (287–212 BC). The story, for the discovery of First Law of Hydrostatics, is very popular
even today in the history of the development of Engineering Mechanics. In the normal course, Hieron
king of Syracuse got a golden crown made for his use. He suspected that the crown has been made
with an adultrated gold. The king liked the design of the crown so much that he did not want it to be
melted,in order to check its purity. It is said that the king announced a huge reward for a person, who can check the purity of the crown gold without melting it. The legend goes that Archimedes, a pure mathematician, one day sitting in his bath room tub realised that if a body is immersed in water, its apparent weight is reduced.

 A Textbook of Engineering Mechanics

Content :
• Introduction
• Composition and Resolution of Forces
• Moments and Their Applications
• Parallel Forces and Couples
• Equilibrium of Forces
• Centre of Gravity
• Moment of Inertia
• Principles of Friction
• Applications of Friction
• Principles of Lifting Machines
• Simple Lifting Machines
• Support Reactions
• Analysis of Perfect Frames (Analytical Method)
• Analysis of Perfect Frames (Graphical Method)
• Equilibrium of Strings
• Virtual Work
• Combined Motion of Rotation and Translation