CONSERVATION OF ENERGY

 CONSERVATION OF ENERGY

Introduction

The ability to do work is called Energy. An object does the work when the force is exerted and displaces an object. Simply energy is that force that causes an object to move. The SI unit  and CGS unit of energy are joule and erg respectively.

There are several forms of energy but the first recognized form of energy is Kinetic Energy(KE) which is defined as the energy possessed by an object due to its motion. 

When the force is exerted in an object it is displaced and work is done so, at this case energy contained in a body is equal to work done by the system and hence both of them same unit

Energy of interacting bodies or particles in a closed system remains constant.

Conservation of Energy

Energy neither can be created nor destroyed but simply can be converted from one form to another where the total amount of energy remains unchanged.

For example, when a freely suspended pendulum swings its potential energy(PE)gets converted into KE. After reaching a certain height the bob of a pendulum stops for a fraction of second and its KE now converts into PE. Due to the effect of gravity the bob of the pendulum comes back to its initial position and hence the PE is converted into the KE. In this case the total amount of KE and PE are equal and the energy is conserved. The sum of KE and PE is constant.

Let us consider an example where two identical balls are rolling towards each other with the equal velocity. They bounce back after colliding and if there is no loss in speed. The collision is regarded as perfectly elastic as there is no loss in energy. In this case both KE and momentum are conserved quantities.

In physics the term conservation means the value doesn't change, meaning the value remains the same before and after an event. These conserved quantities are used in predicting in case of some complicated situations. The three conserved quantity used in mechanics are energy, momentum and angular momentum