Work: Power and Energy- inews71

In this chapter, we will see how a force works. In terms of physics, the word "work" has a definite meaning. We will see that a force working on something can move it and create kinetic energy. This kinetic energy can convert into potential energy and this transformation of energy is a very natural process and different types of energy can convert into one another. The most important aspect of science is energy and energy plays a most important role in the development of mankind so, how energy can be explored from nature will also be discussed.

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Work :
the term 'work' in various manners in our daily life. A gatekeeper guarding a house all day long, sitting on a tool, may claim to have done a lot of work, but in the words of physics, that is not any work. In terms of physics, the word 'work' is well defined. If a force F is applied on any object and the object traverses a distance s during the application of force (that is displacement occurs) then, the amount of work W done by the force is: 

W=Fs

Unit of work: J (Joule)  

Dimension of work [W] = ML2T-2

Force is a vector quantity and the distance traversed or displacement is also a vector quantity but in case of work the product of those two vectors is a scalar quantity. As individual vectors, there is no such condition that the direction of force and distance traveled has to be the same but in this book, we will only discuss the force and distance traveled in the same direction. 

Have you noticed, while discussing work, we said that the 'force' has done the work? A person or a machine may push any object to some distance by applying a force. In terms of daily life, we say that the person or the machine has done the work. But in physics, neither the person nor the machine does the work, always the force applied does the work. This force may be applied by a person or a machine. Let us assume that, you have pushed an object to a distance s by applying a force F and left it after setting it in motion. The object has traveled an additional distanced and at last, it has stopped. How much work is done? The amount of work done is W=Fs, as no force was applied while traversing the distanced, so no work is done.

Energy :
In our daily lives, we use the term energy for different purposes but in physics, it has a definite meaning. Generally speaking, there is no difference between applying energy or applying force, but in physics, these two phrases mean completely different things. In the previous chapter, we have learned what is meant by force, what is meant by energy will be discussed in this chapter. We all have a shallow idea about energy because we mention the words electrical energy, thermal energy when we make casual conversation. Sometimes we even hear about chemical energy or nuclear energy. Though light

It is not mentioned as energy, we can assume that light is one kind of energy too. The energy which is not mentioned in our daily conversation, but will be discussed a lot in physics is kinetic energy. We may think that there are many types of energy in nature, but it is interesting that all kinds of energy are the same and we can only transform them from one to another! So what is energy? The ability to do work is energy! Not only that, when a positive work is done by applying a force on an object, the force creates an energy in that object.

The amount of work done on the object is the amount of energy created in it, and the person who is applying the force has to give exactly the same amount of energy. So now you have understood the meaning of negative work. If any force does negative work on an object, then it is to be understood that a certain amount of energy is taken away from the energy contained in the object. The amount of negative work done is equal to the amount of energy taken away, and he who has applied the force gets this energy anyway. So, on any object 

Doing positive work -, giving energy to the object. Doing negative work —> taking away energy from the object. 

You can clearly understand that energy has no direction and it is a scalar quantity. As we produce energy by doing work or do work spending energy, these two have the same unit and the same dimension.