Work, Energy and Power

Work, Energy and Power

If we have studied physics in high school then we have already studied all these three concepts of work, energy and power in their very detail and that too separately. In this article, we will learn more about them.

The concepts of work, power and energy are related in every detail and form one of the most important topics in the section of classical mechanics in physics. Now all these concepts are related to the concept of displacement in some sort of way. Let us get to know all these concepts in detail.


The concept of work is one of the most important concepts in physics. This concept can be understood in multiple ways namely through theoretical concepts and through multiple equations. If we are to understand work theoretically then we can say that work can be said to be done when an object is experiencing displacement in any form. 

If the object is moving from one place to another then it means that work is being done by that object. Now if we are to understand this by means of a formula then we can say that the work done by an object is the product of the force that is being applied by the object and displacement that is being done by the object. If we introduce the notion of angle into it then we can say that the cosine of the angle is also used in its multiplication. This angle is the angle between the force and the displacement that are being included in the work done. 

More information about work 

There are two types of quantities in work and they are the scalar quantity and the vector quantity. Scalar quantities are the quantities which only have magnitude and no direction whereas vector quantities are the quantities which have both magnitude and direction. Now, work is listed under scalar quantities as it has only magnitude and no direction. 

The unit of force in the equation of work is Newton and the unit of displacement is meters, so the unit of work can be Newton-meter also. The concept of work can also be applied to the concepts of electricity and magnetism but we will learn about them later. 


Power is one of those quantities in physics that can be considered as the backbone of this subject. This is one of the most dealt with concepts of physics daily. The unit of power is the Watt, in honor of the legendary physicist James Watt. The relation between power and work is that power is the derivative of work done with respect to time. 

Power, in terms of a formula, is the product of force and velocity. Now in general, the derivation of a formula also requires the integration of various variables involved in the equation. Now the unit of power except for Watt is also Newton- metres per second. As this unit is the product of force and the velocity itself. 

Average Power 

The concept of average power involves the topic of limits in it. The basic formula of power is the division of the instantaneous work done and the instantaneous time. In this formula, the special case is the fact that the instantaneous time should always be tending to zero. 

If by any chance there is a case of average power then we should know that the formula for average power is the division of the work done by the object or particle and the time taken by the object to do that work. If we want to go into the concepts of rotational mechanics then we should also know that work can also be called the product of torque and angular velocity. 

Power in terms of electricity 

The concept of electrical power can be one of the most important topics in this concept. There are a lot of formulas involved in this concept but we will only be going through the most important formula of power. Though, there are several equations that can be easily found out using different relations in power. 

Now the first formula in this concept is the product of current flowing in the unit of amperes which is its standard unit also and the potential difference that is measured across the component and the unit of it is volts. Now another relationship can be easily withdrawn from here and the relationship comes into play when we express the potential difference discussed above using the ohm’s law and write it as the product of the current and the resistance. So the formula comes out to be the product of the square of current and the resistance. 

Furthermore, we can also express the above relation in the context of potential difference and resistance. It can be written by using the division of the square of the potential difference and the resistance. 


Energy in very simple terms can be written as the amount of work an object or a particle does. The term energy can be divided into many sub topics like kinetic energy and potential energy. We can go into the depth of these energies by using the formulas of these types of energies. Kinetic energy can be expressed as the product of the mass and the square of the velocity and then we have to multiply the product of that by half whereas if we have to express potential energy then we can simply multiply the mass, gravitational constant and the height of the object.


The concept of work, energy and power is one of the important concepts in physics. Many concepts in classical mechanics have been developed using these concepts as the basis or the foundation for them.