In physics there is a phenomenon that is considered fundamental and that we can find in various activities of our day to day, this is mechanical work. Throughout human life, man has used his knowledge, experience and ingenuity to design and build machines capable of facilitating tasks that were previously difficult using physical effort.
These machines are what have allowed us to improve our quality of life, our productivity and, furthermore, to explore the limits of technology. mechanical work It is an essential part of this revolution, which is why, throughout this article, we will talk a little about it, its characteristics, the units of measurement, its importance and more.
Definition and concept of mechanical work
The definition of mechanical work refers to the amount of energy transferred to a system or object through the application of forces over a distance. This type of work occurs when a force acts on an object, causing a displacement in the direction in which the force is applied.
It should be noted that, for mechanical work to be carried out, the displacement must be in the same direction or in a direction parallel to the force exerted on the object. For its part, mechanical work is calculated by multiplying the magnitude of the applied force by the distance in which it is applied and by the cosine of the angle.
If the force and displacement are in the same direction, the angle will be zero (0) degrees, while the mechanical work will be maximum. On the other hand, if the angle is 90 degreesthe cosine of its angle will be zero (0), therefore, no mechanical work is performed.
Mechanical work employs International System of Units for measuring energyand its unit of measurement is expressed in Joules (J).
In this way it is understood that mechanical work is a way of transferring energy from one system or object to anotherproducing effects on its state of movement, speed or kinetic energy.
What are the characteristics of mechanical work?
mechanical work has various characteristics which are considered crucial for the analysis and understanding of the effects it causes in different systems and situations. The main features include the following:
- energy transfer: mechanical work involves the transfer of energy from one system or object to another. When this type of work is done, energy is transferred from the agent that applies the force to the body or object on which said force acts.
- Dependence of displacement and force: These works depend on the displacement of the object and the magnitude of the force that is applied. The greater the applied force and displacement, the greater the mechanical work done.
- Direction of force and displacement: to do mechanical work, the applied force and displacement have to be in the same direction or parallel. If the angle between the force and the direction of displacement is equal to 90 degrees, the cosine of that angle will be zero (0) and no mechanical work is done.
- change in energy of object: when mechanical work is done on an object it can lead to changes in its potential or kinetic energy. When the work is positive it means that energy is transferred to the object, which increases its energy, if it is negative it means that the object has transferred energy to the agent that does the work and its energy is decreased.
What is the formula for mechanical work?
The mathematical formula for calculating mechanical work is expressed as follows: Work (W) = F * d * cos(θ). Where:
- “W” is the mechanical work done
- “F” is the magnitude of the force applied to the object
- “d” is the distance over which the force is applied
- “θ” is the angle between the direction of force and the direction of displacement.
What are the units of mechanical work?
The unit of measurement used to measure mechanical work is Joules (J). This is the unit of energy found in the International System of Units.
The Joules represent the amount of work executed by applying a force of one Newton by a displacement of one meter in the direction of the force. That is why mechanical work is expressed in Joules units, which indicates the amount of energy that is transferred during the process.
What is the symbol for mechanical work?
The symbol used to represent mechanical work in calculations, formulas and/or equations is the letter “W”. That is, when you want to make a calculation or refer to mechanical work within the context of physics, the letter “W” is used as a symbol.
A clear example is the formula for mechanical work: W= F * d * cos(θ), where the “W” represents the mechanical work performed.
What is the product obtained from mechanical work?
When doing mechanical work, the product that is obtained is information about the amount of energy transferred from one object or system to another. Also known as a measure of energy that has been converted or transferred thanks to the application of force to which it was subjected over a distance.
Depending on the context, performing mechanical work different results or effects can be obtainedincluding the following:
- kinetic energy change: It is possible to increase or decrease the kinetic energy of a system or object through mechanical work. If said work is positive, the kinetic energy is increased, but if it is negative, the kinetic energy is decreased.
- lifting objects: when mechanical work is done by lifting objects, energy tends to be transferred to said object, which increases its gravitational power energy. This is what allows the elevation of the object to a greater height.
- work on machines: When talking about machines, mechanical work allows various tasks and processes to be executed. Among them is the transportation of objects, generation of movements or even the transformation of energy.
It is generally understood that, when doing mechanical work, What is usually obtained is information about the amount of energy that was transferred. In addition to information on the effects that said transfer may have on the objects or systems involved.
What are the types of mechanical work?
Within the scope of mechanical work There are several specific types of it, which represent different situations and contexts in which said work proceeds. Among the most common types of mechanical work are the following:
- Lifting work: refers to the work that is carried out when an object is lifted against its force of gravity. For example, when an object is lifted from the ground to a specific or determined height.
- Compression or Expansion Job: This occurs when building jobs for compress or expand springs, gas or any other elastic material. These jobs are concerned with the release or storage of elastic power energy.
- Friction work: these works are done when force is exerted on an object to overcome resistance caused by friction. For example, jobs that are made by pushing an object over a rough surface.
- Horizontal displacement work: This work involves the application of forces to move an object horizontally along a flat surface.
- Work on machines: in this type of work, mechanical work is carried out to operate and/or operate different types of machines. These include machines such as motors, generators, pumps, among others.
These are just a few examples of the most common types of mechanical work, however, there are different situations in which these works are carried out.
What is the importance of mechanical work?
Mechanical work is considered extremely important in several aspects, both in the technology, science and even in everyday life. Among the most relevant reasons that highlight its importance are the following:
- Transfer and conversion of energy: mechanical work is considered essential for the understanding and analysis of how energy is transferred between objects. As well as, it helps to understand the transformation of energy in different forms, such as potential, thermal or kinetic energy.
- Design and operation of machines: mechanical works allow us to understand how forces and motions combine to do useful work. This can be from the movement of a crane, the operation of a car engine, to the generation of electricity in a hydroelectric power station.
- Efficiency and optimization: The study of mechanical work helps to identify how energy losses are minimized and how useful work outputs are maximized. This results in efficient use of resources.
- Applications in physics and engineering: in these sciences, mechanical work provides a framework that leads to the analysis and understanding of phenomena related to energy, displacement and force. It is considered essential in fields such as thermodynamics, dynamics, fluid mechanics and mechanical engineering.
- Improves quality of life: Thanks to this type of work, progress has been made in technology, thus improving our quality of life. These advances allow automating repetitive and heavy tasks, creating devices that facilitate various tasks both in daily life and in science.
Finally, the importance of mechanical work revolves around its role in energy transfer, energy efficiency, machine design and its application in many scientific and technological fields. Besides, These works contribute to the optimization of systems and the progressas well as in the improvement of daily life.
Examples of mechanical work
There are various examples of mechanical work that are applied both in various sciences and in everyday life, some of them are the following:
- when we push a bicycle with a constant velocity, which implies the application of mechanical work. This causes the speed of the bicycle to remain constant as it moves horizontally.
- when pushing a block, which is on a horizontal surface, at a constant speed, requires the use of mechanical work. In such work, the push force must be equal and opposite to the friction force in order to maintain equality and allow the movement to be continuous.
- Mechanical work is applied when lifting a suitcase off the ground and put it on a shelf.
- When we push a shopping cart mechanical work is carried out by the supermarket.