Introduction To Energy And Its Types

The concept of energy is one of the most important physical concepts in both contemporary science and engineering practice. In everyday usage, we think of energy in terms of the cost of fuel for transportation and heating electricity for light, current and appliances and the foods we consume. However, these ideas do not really define energy. They only tell us that fuels are needed to do jobs and that those fuels provide us with something we call Energy.

Energy can be defined as the ability to do work. Because in terms of physics also we need the energy to make our work done, to make something move or to make an object into motion. In physics, energy is a conserved quantity that means energy is always conserved. It can't be created nor be destroyed. It can just change its forms known as the law of conservation of energy or thermodynamics first law.

Energy is present in different forms, including mechanical energy, electromagnetic energy, chemical energy, thermal energy and nuclear energy etc. The various forms of energy are related to each other through the fact that when energy is transformed from one form to another, the total amount of energy remains the same. This is the point that makes the energy concept so useful. That is, if an isolated system loss energy in some form, then the law of conservation of energy says that the system will gain an equal amount of energy in other forms. The transformation of energy from one form into the other essential part of the study of physics, engineering, chemistry, biology, geology and astronomy. The word energy is very often used in our daily life, but in science, we give it a definite and precise meaning. Consider the following examples: when a fast-moving ball hits a stationary wicket, the is thrown away. Similarly, an object when raised to a certain height gets the capacity to do work. An object which has a capacity to do work is said to possess energy. The object which does the work loses energy and the object on which the work is done gains energy. An object that possesses energy exerts a force on another object. When this happened, energy is transferred from the former to the latter. The and second object may move as it receives energy and therefore, does some work. Thus, the first object had the capacity to do work. This implies that any object that possesses energy can do work.

Units of Energy:

In 1843 Joule discovered an instrument known as Joule's apparatus used for measuring the mechanical equivalent of heat. Later the SI unit of energy is also known as Joule. It can be defined as a force of 1 Newton applied at a distance of 1 meter. And its CGS unit is erg which is equivalent to 1 dyne of force applied at a distance of 1 cm.

Mechanical Energy And Its Types:

The energy acquired by the objects upon which work is done is known as mechanical energy. Mechanical energy is the energy that is possessed by an object due to its motion or by the virtue of its position. Mechanical energy can be of kinetic energy (in motion) or potential energy (stored energy at rest). Objects are said to have mechanical energy if they are in motion or if they are at some position relative to a zero potential energy position (eg a brick lying at some height above the ground).

Mechanical energy is two types:

• Kinetic energy
• Potential energy

Kinetic Energy:

The kinetic energy of an object is an energy that is possessed by its motion eg a car is moving with some speed have kinetic energy in it r any object that is in motion said to have kinetic energy in it. In simple pendulum when the bob is at its mean motion, it is said to have maximum kinetic energy. It can be defined as a work needed to accelerate a body of a given mass from rest to its stated velocity. In classical mechanics, it is measured by the formula 

KE= 1/2mv^2

where m is mass of the object and v is the velocity with which it is moving.

Potential Energy:

The potential energy of an object is the energy possessed by a virtue of its position eg: an object is placed above the ground or a dam, etc.  There are different types of potential energy like gravitation potential energy or elastic potential energy, etc. In classical physics potential energy of an object is measured by the formula:

U=mgh

where m is the mass of the object, g is the acceleration due to gravity and h is the height at which the object is displayed.

These all energies are interchangeable like eg: in a dam, water is stored therefore the water is having potential energy but when the barrier of the dam is open for the flow of water to the home then it converts into kinetic energy. Likewise, there are many such examples.