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If we look up the word “work” in the dictionary of the Spanish language, we will get several different meanings, among which are included:
- Action and effect to work.
- Something that is the result of human activity.
- Operation of the machine , piece, tool or utensil that is used for some purpose.
- Human effort applied to the production of wealth, as opposed to capital.
- Place where you work.
- Product of the force by the distance that its point of application travels.
However, for some scientific disciplines, the meaning of work goes beyond these definitions. This concept is widely used, especially in physics and chemistry, since it is part of countless processes and phenomena. Generally, the concept of work is also related to the definitions of energy and power.
Energy, work and power
To understand what exactly work is, it is necessary to first consider the definitions of energy and power.
Energy
Energy can be defined as the ability to do work . In nature, energy is used in a large number of situations: to move an object, turn on a device, perform vital functions, increase or decrease the temperature, among others.
Therefore, energy is considered to be the ability of bodies to produce changes in themselves or in others. These changes occur due to their interactions and the energy transfers that take place.
Energy can be thermal, electrical, chemical, kinetic, potential, nuclear, light, etc. Some of the units used to measure it are:
- The joule (J): one J unit is approximately equivalent to the energy needed to lift a 100-gram body one meter high.
- The calorie (cal): amount of energy needed to raise the temperature of 1 g of water by 1ºC. Its equivalence in joules is 1 cal = 4.18 J.
- The Kilowatt-hour (kWh): This measure is the energy that is developed by a power of 1000 watts during 1 hour. Its equivalence in joules is: 1 kWh = 3,600,000 J.
The power
Power is a quantity that relates the work done to the time it takes to do it . It can also be defined as the rate at which work is done or energy is used.
According to the International System of Units of Measurement, power is measured in watts (W), work in joules (J), and time in seconds (s). For example, if 100 joules of work are produced in one second, the power is 100 watts.
job definitions
Work is an activity that uses a force and moves in the direction of that force. Forces are interactions that occur between bodies.
Work is used to measure the consequences caused by the action of a force in a system. Therefore, work can also be defined as the measure of the action that forces exert on a system.
It is important to note that in order to count as ‘work’, the force must produce a change. For example, if a car is pushed, it is evident that a force is being exerted, but if it cannot be moved, the work is considered zero.
Kinds of work
There are numerous types of work depending on the kinds of forces used. These might be:
- Gravitational work: in this type of work the force of gravity intervenes. It occurs when an object moves under the action of a gravitational force.
- Electrical work: here the electrical force participates and it is the work that said force does on a charge that moves from point A to point B.
- Pressure-volume work: This is the work done by some gases.
- Mechanical work: it is the one that is carried out when changing the position of the bodies or when moving them. The energy that allows mechanical work to be done can be:
- Kinetics: if the movement of objects changes. Kinetic energy is the energy possessed by bodies because they are in motion.
- Potential: if the height of the objects is modified with respect to the ground level. Potential energy is that which is “stored” in bodies.
How work is measured
In both physics and chemistry, mechanical work appears most frequently. It is a magnitude that is measured indirectly, therefore, it is calculated from the force that is exerted and the effects it produces. Since work is equal to the product of force and the distance the object is moved, we can measure it using the following formula:
t=F*d
where “t” is work, “F” is the opposing force, and “d” is distance.
Another way to measure mechanical work is:
t = m*a*d
where “m” is mass, “a” is acceleration, and “d” is distance.
Other job characteristics
Work can be positive or negative. This depends on certain characteristics, such as:
- If the force is exerted in the same direction as the movement, the work is positive. This occurs when the work of a car engine causes it to propel in the direction of travel.
- On the other hand, if the force acts in the opposite direction to the movement, negative work is produced. This is the case of the work carried out by the brakes of a car when they try to stop the movement, applying a force against it.
Bibliography
Garcia Taravilla, ME; Martí Oliet, VM Generation and energy recovery. (2020). Spain. Editions 1.
Rivas, JM; Artero García, A. Matter and energy: science, physics and chemistry. (1974). Spain. Everest.
Prentice Hall. Movement, forces, and energy. (1994). Spain. Prentice Hall.
RAE. Spanish dictionary. (2021). Available at: https://dle.rae.es/trabajo
ICT Resources Work and energy. (Chapter 6). Fortnight. Available at: http://recursostic.educacion.es/newton/web/materiales_didacticos/EDAD_4eso_trabajo_energia/impresos/quincena6.pdf
