Newton's laws of motion help us to analyse many kinds of motion. But the analysis is complicated, requiring details about the motion that we simply do not know.
Long ago, people used to trade by only exchanging products when the concept of 'money' was yet to be introduced. Now we do know the concept of money. But if we were to define money, it would not be an easy task. But we do know it can manifest itself in many forms. Money is a concept imagined by man and it plays a very big role in the present world.
The concepts of 'energy' or 'work', play the same role in physics. To understand work, let us look into the following problem. In the weightlifting competition of the 1996 Olympics, Andrey Chemerkin lifted a record-breaking 260.6 kg to a height 2m. In 1957, Paul Anderson lifted a wooden platform and a load placed on it, with his back, through a height of one centimetre. The weight of the load was 27900 N. Who did more work - Chemerkin or Anderson? Let us try to find the answer.
The word 'work' as understood in everyday life, has a different meaning in scientific sense. A student carrying his bag full of books feels tired after sometime. We feel he has done work. But physics says that the work done by him against gravity is zero. Then, when is work done?
Work is done by a force when the force produces a displacement in the body on which it acts, in any direction other than the direction perpendicular to the force.
