24-01-2013, 03:48 PM
WORK AND ENERGY
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WORK
We all are familiar with the word ‘work’. We do a lot of work everyday. But in science ‘WORK’ has another meaning. According to science, a work is said to be done only when a force act on an object which displaces it or which causes the object to move. Therefore the two conditions required to prove that a work is done are : A force should act on an object. The object must be displaced. If any one of the above conditions does not exist, then work is not done. WORK is a scalar quantity, i.e. it has only magnitude and no direction. The unit of WORK is Neuton metre (N m) or joule (J).
WORKING HARD
I think Hard work is necessary when you are at very initial phase of your work, you need to collect all those information which is required, then how smartly and efficiently you put those into practice is your Smart Work. Experience teaches you all how to work smartly but to get those experience you need to work hard. I think both Hard Work and Smart Work re inter related. Smart work is absolutely necessary to achieve your goal within desirable time.
SCIENTIFIC CONCEPTION OF WORK
To understand the way we view work and define work from the point of view of science Let us consider one situation:
Push a pebble lying on a surface the pebble moves through a distance. You exerted a force on the pebble and the pebble got displaced. In this situation work is done.
WORK DONE BY CONSTANT FORCE
Let a constant force. F, act on an object. Let the object be displaced through a distance, S in the direction of the force . Let W be the work done We define work to be equal to the product of the force and displacement.
Work done = force x displacement
W = Fs
ENERGY
Life is impossible without energy. The demand for energy is ever increasing. Where do we get energy from? The sun is the biggest natural source of energy to us. Many of our energy source are derived from the sun. We can also get energy from the nuclei of atoms, The interior of the earth, and the tides. Can you think of other sources of energy?