Work

WORK

INTRODUCTION:
The terms ‘work’, ‘energy’ and ‘power’ are frequently used in everyday language. A farmer clearing weeds in his field is said to be working hard. A woman carrying water from a well to her house is said to be working. In a drought affected region she may be required to carry it over large distances. If she can do so, she is said to have a large stamina or energy. Energy is thus the capacity to do work. The term power is usually associated with speed. In karate, a powerful punch is one delivered at great speed. In physics we shall define these terms very precisely. We shall find that there is at best a loose correlation between the physical definitions and the physiological pictures these terms generate in our minds. 

DEFINITION OF WORK:
Work is said to be done when a force applied on the body displaces the body through a certain distance in the direction of force.
               \( W = \overrightarrow F .\overrightarrow S = F.S.\cos \theta \,\,\,(between\,F\theta S\,\,and\,S\,\,and\,\cos \theta \,.\,not\,there) \)

DIMENSSIONS &UNITS OF WORK:
Dimension : As work =  Force x displacement 
     [W] = [Force] x [Displacement] 
            = [MLT^-2] x [L] = [ML²T^-2] 
Units :The units of work are of two types