Work is a basic concept in science that describes the transfer of energy to or from an object by exerting force along its displacement. This is done in a multiplicative fashion, where the product of the magnitude of the force applied and the distance travelled equals the work that has been done.
It is the connection between a force and an object’s displacement (or energy transfer). In physics, this can be expressed in terms of joules and foot-pounds.
In the mathematical language of science, work can be expressed as the product of the force and the distance displaced by a body. The corresponding unit of measure is the joule, which is the equivalent to the amount of energy expended when one newton is exerted on an object moving a distance of a meter.
This is a simple formula, but it illustrates the two conditions for work to be performed: The force must be acting on the object and the displacement must be in the same direction as the force. In some cases, the force and the displacement may be in reverse directions. For example, if an object is dropped off a table and hits the ground, the force (gravity) acts on it causing it to be displaced in a downward direction.
The first condition for work to be done is easy to determine. In the picture below, is the truck doing work? Click on the arrow that represents the force and the direction of motion to determine whether the truck is doing work or not.
In the second condition, it can be a little more difficult to determine. In the case of a student pushing a box with her arms, it is a good idea to ask someone else for help to verify that she is doing work. Then, she can look at the resulting answer to see whether it is negative or positive work. A negative answer means that the box is preventing her from doing work. This can be a frustrating and exhausting situation for the student, but it is not a work-related problem.
