What is energy?
if a person can do a lot of work we say that he has a lot of energy or he is very energetic. In physics also anything which is able to do work is said to possess energy. Thus, energy is the ability to do work. For example, to cut a log of wood into small pieces, we have to raise the axe vertically above the log of wood and some work has to be done in raising the axe. If the axe is now allowed to fall on wood, it can do work in cutting the wood. Thus, the work done in raising the axe has been stored up in it, giving it the ability for doing work. The amount of energy possessed by a body is equal to the amount of work it can do when its energy is released. It should be noted that whenever work is done, energy is consumed. Energy is scalar quantity. It has only magnitude but no direction.
Unit of Energy
The units of work and energy are the same. So, the SI unit of energy is joule (which is denoted by the letter J ) whenever work is done in equal amount of energy is consumed. The energy required to do 1 joule of work is called 1 joule energy.
Different Forms of Energy
1. Kinetic energy
2. Potential energy
3. Chemical energy
4. Heat energy
5. Light energy
6. Sound energy
7. Electrical energy
8. Nuclear energy
The energy of a body due to its motion is called Kinetic energy. A moving hammer drives a nail into wood because of its kinetic energy and a moving bullet can penetrate even I steel plate due to its kinetic energy which it has on account of its high speed. In fact, every object around us which is moving possess kinetic energy. In other words, every object around us which has speed poses kinetic energy. For example ; a runner has kinetic energy, a running motorcycle has kinetic energy.
Potential energy
The energy of a body due to its position or change in shape is known as potential energy. Actually, the energy of a body due to its position above the ground is called gravitational potential energy and the energy of a body due to change in its shape and size is called elastic potential energy. Elastic potential energy is associated with the state of 'comparison' or 'extension' of an object. For example, the energy possessed by a 'compressed spring' or an 'extended spring' is the elastic potential energy. The gravitational potential energy as well as elastic potential energy are commonly known as just potential energy.
The water in a tank on the roof of a building possesses potential energy due to its position above the ground.
Comments
Post a Comment