The Meaning of Work

In everyday conversation, we use the word work in various ways. "Going to work", "doing homework", "a writer's work" these are some common expressions using the word. The meaning of "work" varies. But, to the scientist, "work" has the same meaning every time it is used. In science, we say that "work" has been done only if a force of some kind has moved an object from one place to another place. "Work is done when a force moves an object through a distance" is how scientists describe it. 

You are doing work, in the scientific sense, if you lift a bag of potatoes onto your shoulders. You use a force to raise the bag through the distance from the floor to your shoulders. Once the bag is on your shoulders, no more work is being done because there is no motion. The amount of work you did depends on the amount of force you had to use and the distance through which you moved the potatoes. For example, you do work whenever you stretch a spring or an elastic band. The more you stretch it, the more work you do.

Machines 

The modern world is filled with machines. Some of them are very simple, such as the can opener, the shovel, and the saw Others are more complicated, such as the bicycle, the lawn-mower, and the crane. All machines are designed to make work easier. There are three ways in which they can do this by increasing the force, by increasing the speed, and by changing the direction of the force. Here is an example of each of the three ways.