Work and Energy

Introduction

     For a layman the term 'work' implies any activity resulting in muscular or mental exertion.

Work and Measurement of Work

     Work is said to be done when a force acts on an object and the point of application of the force moves in the direction of force.

SI Unit of Work

     One joule is the work done when the point of application of a force of one newton moves through a distance of one metre in the direction of force.

Energy

     Energy is the capacity to do work. Energy is measured by the amount of work that a body can do. Therefore, SI unit of energy is also joule.

Kinetic Energy

     Kinetic energy is defined as the energy possessed by an object by virtue of its motion.

Momentum

     Momentum of the body is defined as the product of its mass and the velocity.

Potential Energy

     Potential energy of an object can be defined as the energy possessed by the object by virtue of its position or condition.

Law of Conservation of Energy

     Law of conservation of energy states that the energy can neither be created nor destroyed but can be transformed from one form to another.

Power

     As energy is the capacity to do work, power can also be defined as energy consumed in unit time.

Commercial Unit of Energy

     The SI unit joule is too small to express very large quantities of energy. Hence we use a bigger unit called kilowatt hour (kWh) to express energy.

Summary

     Law of conservation of energy states that energy can neither be created nor destroyed but can be transformed from one form to another.

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