NEET Physics WPE

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 a loose correlation between the physical definitions and the physiological pictures these terms generate in our minds.

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.

Work Done by a Constant Force

Nature of Work Done

 

 

Zero work

 

Work Done by a Variable Force

Dimension and Units of Work

Work Done Calculation by Force Displacement Graph

 

 

Work Done in Conservative and Non-conservative Field

Work Depends on Frame of Reference

With change of frame of reference (inertial), force does not change while displacement may change. So the work done by a force will be different in different frames.

Energy:

(6) Transformation of energy: Conversion of energy from one form to another is possible through various devices and processes.