The general form of the work equation is:
Here is an example of a situation where a force is applied and no work is done: A man holds a 50 N weight. No work is done (even though he must exert a force to hold the weight) because there is no displacement parallel to the direction of the weight.
Here is an example of a situation where there is a force applied and there is displacement and no work is done against the object's weight: A man walks around the room holding a 50 N weight. The object's weight acts down. For work to be done against the weight there has to be displacement in the direction of the weight (either up or down). There is none so no work is done against the weight. There is work done against friction as the man walks around the room.
In the drawing, F is applied at angle q to the horizontal. The force doing the work is the horizontal component of the force since it is the component that is parallel to the horizontal displacement. In this type of situation, the form of the work equation would be
Work can be represented graphically. If you plot force vs displacement, the area under the curve represents the work done.
Calculus application: Integration is used to find the area under a curve. If you integrate this curve, you have found the work done.
Types of simple machines:
Efficiency can also be expressed in terms of advantage: