Work, Energy and Power

Upon completion of this lesson, student must be able to:

  • Define work, energy and power.
  • Differentiate the work done against gravity and work against friction.
  • Describe various forms of energy.
  • Solve numerical related to work, energy and power.



Work is done when a force acts on an object to displace it. One joule is the amount of work done when a force of one newton acting on a body moves it through a distance of one meter in the direction of force. This note is about work, power and various form of energy.


The capacity of a body to do work is called the energy of the body. Conversion of energy from one form to another form is called transformation of energy. Energy can neither be created nor be destroyed but can only be changed from one form to other. This note provides information about different types of energy.


The rate of doing work is called power. Its SI unit is Watt (W). Work energy and power are interrelated terms. This note provides us an information about power, conversion and numerical solution of power.