Work, in general language, means to exert effort physically or mentally. It can also refer to an activity that needs to be done in order to earn money or achieve something. For example, when one writes an essay, studies for exams, or performs a piece of music, they are doing work. It can also mean someone’s job, a particular career, or a profession. For many, work is a part of their lives and it influences every aspect of their life, including family, health, finances, and relationships. However, there is another definition of work that has more to do with the transfer of energy. In Physics, the concept of work is based on the connection between force and displacement. It is defined as the product of a component of force in the direction of the displacement and the magnitude of the displacement. The formula for work is W = fd and it is a scalar quantity.
In everyday life, when we use the term ‘work’, it often refers to a difficult task. For instance, if we work on our homework for weeks, study for an exam, or carry a heavy load for a long distance, we are often considered to be doing hard work. However, when it comes to Physics, the term ‘work’ has a different meaning. In fact, according to the Science of Physics, an activity cannot be considered as work unless it involves a force and some kind of displacement.
To calculate the amount of work done by a force, three quantities are needed: the force, the displacement, and the angle between the force and the displacement. When the displacement is in the same direction as the force, then the work done by that force is positive. For example, when a ball falls freely under gravity, the amount of work done is positive because the force is in the same direction as the displacement. However, when the displacement is in the opposite direction from the force, then the work done by that Force is negative.
Whether an activity is positive or negative, the amount of work that is performed is the same as the increase in the energy of the object. This is because energy is transferred from the object to the force. The units for work are the same as those for energy and include the SI unit of joule, newton-metre, kilogram-second, and erg. The work that is done on a body by gravity, for example, is positive because the energy of the ball is transferred from the Earth to the force of gravity. The same is true for all other forms of mechanical work. The only exception is frictional work, which is always negative.