Work is an activity that involves exerting force on an object to cause the displacement of the object. The quantity of work is equal to the product of the force and the distance, and is measured in joules (J), which are also the same units used for energy. Work can be positive, negative or zero, depending on the direction of the displacement vector with respect to the force. For example, friction acting on an object falling towards the ground will do negative work because it causes the object to move in the opposite direction of the force. Conversely, a rock being thrown upwards by the force of gravity will do positive work because it causes the object to move in a direction parallel to the force of gravity.
A block is resting on a frictionless surface and a constant force F acts upon it. The action of the force moves the block a distance d. The amount of work done is equal to the scalar product of the force and the displacement, where F, d, and a are the three key variables. In most cases, a is the angle between the force and the displacement vector, and can be found using the following equation:
In this case, a is 90 degrees. For a vector, the unit of work is the dot product of the force and the displacement, or simply the square root of the magnitude of the force times the magnitude of the displacement. The SI unit for work is the joule, named after 19th-century English physicist James Prescott Joule.
In the context of a person’s career, work can refer to the amount of time and effort that is spent in a job or occupation. It can also refer to a physical or mental activity that is undertaken with the purpose of producing an end result, such as scholarly research, artistic creation, or manual labor. Lastly, the word can also refer to a piece of art or music created by an artist or composer. When used as a verb, the word work can mean to expend physical or mental effort in an attempt to produce something, to toil or labor, to perform a task or chore, to complete a project, or to help someone. It can also refer to a particular activity, such as teaching, consulting, or counseling. In this case, the term work is often accompanied by an adjective such as hard, serious, or dedicated. A common idiom is to “work the problem” in order to solve a difficult situation. For instance, a teacher may be forced to work through a class of difficult students in order to teach them. Similarly, an employer may “work the staff” in order to manage employees effectively. In this sense, the phrase is meant to convey that one is working diligently and is achieving results. In addition, the use of this phrase is usually accompanied by an emphasis on the importance of good communication and teamwork.