WORK

As a physical concept, work is the result of the action caused by force. We define work as the result of the amount of force that acts upon an object and the distance (parallel) the object traveled. Hence work requires not only a force but also a motion or the movement of an object traveled through a distance.

The figure below illustrate the concept of work. In the picture below, a force is being applied to the wall, but no work is being done since the wall didn't move a inch. For example, when a person is mowing the lawn with a push-type lawn mower, only the force component parallel to the lawn (the horizontal force) is used to done the work. The vertical component of the force is doing no useful work, since force is tending to push lawn mower into the ground level. When the applied force is perpendicular to the distance through which the object is moved, no work will be done.

 A force is applied to the wall, however, no work is done, because there is no movement.

The most important properties of work is that it is a scalar quantity. Both the force and the parallel distance have direction associated with them, but work does not have a direction associated with it. Work is expressed only as a magnitude with the proper units. It does not have a direction associated with it.

Since work is the product of a force and a distance, then the units of work are the units of force times length. In the SI measuring system, the units of work are the newton-meter. This unit is given the special name of joule. One joule is equal to the amount of work done by 1N (Newton) with a distance of one meter.