The concept of strength has a large number of denotations in different fields, being in some synonymous with physical and mental strength, resilience and resistance to events.
But beyond that, we also call force to be one of the main magnitudes of physics, studied from basic physics to the most complex branches of science, and involved in a large number of phenomena, actions and reactions.
Therefore, at the level of physics we can speak of different types of force, About which we will make a brief mention in this article.
What do you call strength?
Before starting to talk about the different typologies or categories that have been established during the analysis of the different types of force, it is necessary to establish a brief definition of the concept.
Generically, we can define force as a physical quantity of vector type, Which is associated and considered as the cause of the capacity to generate a displacement or a movement with acceleration by a body or an object, a change of its structure or even of its state of rest when to achieve this it is necessary to exert a resistance to another force. To be properly defined, it should be noted that all forces have a specific point of application, direction and intensity that will determine the final behavior of the object.
How awesome the force has a unit of measurement, the Newton (In honor of Isaac Newton, who is believed to be the first to establish a mathematical formula for his calculation), which refers to the amount of force required to generate one meter per second squared acceleration in a body of a kilogram of mass. In addition, there are other units of measure as well, such as lunch.
It is possible to classify the types of force according to different criteria. Let’s see.
1. Depending on specific parameters
One can find classifications made on the basis of aspects such as their permanence, the existence or not of direct contact between bodies or their way of acting. The following types of force are examples.
1.1. fixed forces
By fixed or permanent forces we mean all those inherent in the body or the object in question and which derive from its structure or its configuration, and from which it is not possible to escape. One of the most visible is the weight, Product of the mass of the body and the gravitational pull to which it is subjected.
1.2. variable forces
Also called intermittent, are the forces that are not part of the structure of the object or body in which the movement or change occurs but comes from other bodies or elements. An example would be the force applied by a person to a cart to move it.
1.3. of contact
Contact forces are understood to mean all those which are characterized by the need for contact between bodies or elements in order to generate a movement or a change in structure. It is about the forces traditionally worked by classical mechanics, As we will see later.
1.4. At a distance
On the contrary than in the previous case, the forces at a distance are all those in which it is not necessary for there to be contact between the bodies in order to obtain an alteration of the structure or a displacement of the bodies. An example of this would be electromagnetism.
All of these forces that do not vary in intensity, direction or location are termed static, remaining virtually constant whenever they exist. An example would be the force of gravity.
Dynamic forces are all those in which the general values that are part of the force they vary constantly and abruptly, Change of address, place of application or intensity.
This name is given to the forces which are applied to an object in order to move it or modify its structure, not coming from the object itself but from an external element. Pushing a little this would involve applying a force of action.
All those which are generated by the body itself are called as such in response to the application of an external force, From a given point of application. In the above case, the displaced body would exert a reaction force towards us.
By this we mean the forces opposed to each other having the same intensity but the addresses are completely opposite, This causes the body in question to remain in a specific position. This type of force would be illustrated with any stationary object on the ground or with two people of the same force pushing each other at the same time.
We refer to those forces that when applied to a specific body, they generate their movement, As there is not enough balance or opposing force to prevent it.
2. In classical mechanics: contact forces
There are many and varied types of force that can be found in nature, but generally when the concept of force begins to be studied physically, it is generally used in the context of classical mechanics, referring to a type of force called contact. Within these we can find the following types of strength.
We understand as normal force this force it is exerted by the interaction between two bodies in contactAs for example an object and the earth, exerting a reactive force to that of the weight which would go in the opposite direction to that of this one.
As applied force, we understand that force that one body uses on another that causes accelerated movement or a change in the structure of the object. It is a force of direct contact.
Friction or the force of friction is that force which appears before the contact of two bodies and which acquires an address directly opposite to the applied or normal force. For example, when pushing an object, it offers resistance produced in large part by the force of friction against the ground.
Another analogous form of this type of force, sometimes classified independently, is that of air resistance. This force is what explains, for example, that two objects of the same mass launched at the same time from the same height can take a different time to reach the ground (air friction), or that an object pushed by a slight slope can end up braking. .
We call the elastic force that occurs when a surface or object is held in a non-equilibrium position by a given force, appearing as a reaction that seeks to restore that initial position or equilibrium. That is, this is what happens when a body is 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 rubbers which seek to return to their original position.
We are dealing with a special type of force, characterized by being able to transmit a force between different bodies and which is generated when two opposing forces pull a body in opposite directions without breaking. It can be used to generate systems that distribute the force to be applied to generate movement. Tractive force is that force that allows us to use, for example, pulleys to move heavy objects.
A force of inertia or fictitious force is one with which a body is moved by the resultant of forces that have been previously applied to it, although the body or object that generated this force has already ceased to apply it directly. It is the force with which a body maintains its state of motion, in the same direction of acceleration. This is the case, for example, when the body of the occupants is struck by a collision or sudden slowdown in a car it tends to project in the same direction than that followed by the vehicle.
3. The fundamental forces
In addition to those of classical mechanics and relating to macroscopic bodies, one can find other great forces that refer to the relations that have the particles of matter to each other or the existence of forces at a distance, being its product study mainly of modern physics and explaining a large part of the previous ones.
3.1. gravitational force
We call this gravitational force this force of the attraction existing between objects and the intensity depends on their masses and the distance between them. The most studied gravitational force is that of the planet itself, which attracts bodies above it to its surface, being one of the best known distance forces. It is also the force that causes the planets to orbit the stars. It is also important in amounts such as weight.
3.2. electromagnetic force
While in the past we spoke of magnetic and electrostatic forces separately, the gradual study of the properties of these forces has shown that they are in fact interdependent.
It’s a question of strength through which electric 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 relationships occur in moving particles, electromagnetic fields are generated.
3.3. Weak nuclear force
Nuclear force is probably one of the most difficult forces to understand for those not well versed in physics. In the case of a weak nuclear force, we are dealing with a type of force which allows the decay of neutrons and radioactivity. In addition to generating forces of attraction and repulsion, it allows a particle to change.
3.4. Strong nuclear force
Stemming from particle physics, the strong nuclear force is that which allows two particles which, by electric charge, should repel each other-stay together, which allows the existence of a proton nucleus in most molecules.
- Hellingman (1992). “Newton’s Third Law Revisited.” Phys. Educ. 27 (2): pages 112 to 115.
- Hibbeler, RC (2010). Mechanical Engineering, 12th edition. Pearson Prentice Hall. p. 222.
- Newton, Isaac (1999). The Principles Mathematical principles of natural philosophy. Berkeley: University of California Press.