The 20 types of force (according to physics)
The concept of force has a large number of denotations in different areas, being in some synonyms of strength both physically and mentally, resilience and resistance to events.
But beyond that, we also call force one of the main magnitudes of physics, studied from basic physics to the most complex branches of science, and which participates in a large number of phenomena, actions and reactions.
So that, at the physics level we can talk about different types of strength , about which we will make a brief mention in this article.
- Related article: "The 15 types of energy: what are they?"
What do we call force?
Before starting to talk about the different typologies or categories that have been established when analyzing different types of force, it is necessary to establish a brief definition of the concept.
In a generic way we can define force as a physical magnitude of vector type , which is associated and considered the cause of the ability to generate a movement or movement with acceleration by a body or object, a change in its structure or even its resting state when to achieve this must be exerted a resistance to another force. In order to be correctly defined, it should be noted that every force has a point of application, a direction and a specific intensity that will determine the final behavior of the object.
How magnitude is the force has a unit of measurement, the Newton (in honor of Isaac Newton, who is considered the first to establish a mathematical formula for its calculation), which refers to the amount of force needed to generate an acceleration of one meter per second squared in a body of one kilogram of dough. In addition there are also other units of measurement, such as dyna.
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Types of force
It is possible to classify the types of force following different criteria. Let's see them
1. Based on specific parameters
We can find classifications made based on aspects such as their permanence, the existence or not of a direct contact between the bodies or their way of acting. An example of this are the following types of force.
1.1. Fixed forces
Fixed or permanent forces are understood as all those inherent in the body or object in question and that are derived from its structure or configuration, and from which it is not possible to escape. One of the most easily visible is the weight , product of the mass of the body and the gravitational attraction to which it is subjected.
1.2. Variable forces
Also called intermittent, are those forces that are not part of the structure of the object or body in which the movement or change occurs but rather comes from other bodies or elements . An example would be the force applied by a person to a car to move it.
Contact forces are understood as all those that are characterized by the need for a contact between bodies or elements in order to generate a movement or structural change. It's about the forces traditionally worked by classical mechanics , as we will see later.
1.4. From distance
Unlike in the previous case, the remote forces are all those in which it is not necessary that there is a contact between the bodies to achieve an alteration of the structure or a displacement of the bodies. Example of this would be electromagnetism .
All those forces that do not vary in intensity, direction or place are denominated as static, remaining practically constant whenever they exist. An example would be the force of gravity.
The dynamic forces are all those in which the general values that are part of the force they vary constantly and abruptly , changing its address, place of application or intensity.
1.7. Of action
They receive this denomination those forces that are applied on an object with the purpose of displacing it or modifying its structure, not arising from the own object but from some external element. The fact of pushing something would imply being applying a force of action .
They are denominated as such all those that are generated by the own body in response to the application of an external force , from a specific application point. In the previous case, the moved body would be exerting a reaction force towards us.
They are understood as those forces that oppose each other having the same intensity but whose directions are totally contrary , something that generates that the body in question stays in a concrete position.This type of force would be exemplified by any object that was still on the ground or with two people of the same strength who would push each other at the same time.
We refer to those forces that in applying on a concrete body generate their movement , in the absence of a balance or a sufficient contrary force that prevents it.
2. In classical mechanics: the contact forces
There are many and diverse types of force that can be found in nature, but usually when you begin to study physically the concept of force is often used in the context of classical mechanics, making reference to a type of forces called contact. Within these we can find the following types of force.
We understand as normal force that force that is exerted by the interaction between two bodies in contact , like for example an object and the ground, exerting a reactive force to the one of the weight which would go in opposite direction to the one of this one.
As an applied force we understand that force that one body uses on another and that causes an accelerated movement or a change in the structure of the object. It is a direct contact force.
The friction or force of friction is that force that appears before the contact of two bodies and that Acquires an address directly opposite to the force applied or normal . For example, when pushing an object this is offering a resistance produced largely by the force of friction against the ground.
Another analogous form of this type of force, which is sometimes classified independently, is that of air resistance. This force is what explains for example that two objects of the same mass thrown at the same time from the same height may take a different time to reach the ground (air friction), or that an object pushed by a slight slope may end up slowing down .
We call elastic force to that which occurs when a surface or object is held in a position of non-equilibrium by a particular force, appearing as a reaction that seeks to restore this initial position or balance. That is, it is the one that occurs when a body subjected to a force that has deformed it try to return to its original state . A typical example can be found in springs, springs or stretched rubber bands that seek to return to their original position.
We are facing a peculiar type of force, characterized by being able to transmit a force between different bodies and that is generated when two opposing forces pull a body in opposite directions without breaking it . It can be used to generate systems that distribute the force to be applied to generate the movement. Tension force is that force that allows us to use, for example, pulleys to move heavy objects.
2.6. Of inertia
It is called force of inertia or fictitious force that with which a body is moved by the resultant forces that have been previously applied even when the body or object that has generated that force has already stopped applying directly. It is about the force with which a body maintains its state of motion, in the same direction of acceleration. This is what happens, for example, when faced with a crash or sudden deceleration of a car the body of the occupants it tends to project in the same direction than the one that followed the vehicle.
3. The fundamental forces
In addition to those of classical mechanics and related to macroscopic bodies, we can find other major forces that refer to the relationships that have the particles of matter with each other or the existence of forces at a distance, being their study product mostly of modern physics and allowing explain much of the previous.
3.1. Gravitational force
We call gravitational force to that force of attraction between the objects and whose intensity depends on their masses and the distance between them . The most studied gravitational force is that of the planet itself, which attracts the bodies that exist on it towards its surface, being one of the best known remote forces. It is also the force that causes the planets to orbit around the stars. It is also important in magnitudes such as weight.
3.2. Electromagnetic force
Although formerly we spoke separately from the magnetic and electrostatic forces, the progressive study of the properties of these forces have shown that they are in fact interrelated.
It's about strength through which the electrical particles are attracted or repelled by other charged particles either with the opposite sign (force of attraction) or with the same (of repulsion). When these relations are produced in moving particles, electromagnetic fields are generated.
3.3. Weak nuclear force
Probably some of the hardest forces to understand for those not versed in physics is the nuclear force. In the case of the weak nuclear force, we are facing a type of force which allows the disintegration of neutrons and radioactivity . In addition to generating forces of attraction and repulsion allows a particle to change.
3.4.Strong nuclear force
Coming from particle physics, the strong nuclear force is one that allows two particles that should be repelled by electrical charge to remain together, something that allows the existence of a nucleus of protons in most molecules.
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- Hibbeler, R. C. (2010). Engineering Mechanics, 12th edition. Pearson Prentice Hall. p. 222
- Newton, Isaac (1999). The Principia Mathematical Principles of Natural Philosophy. Berkeley: University of California Press.