What are forces in physics

In physics, a force is defined as an interaction that can change the state of motion or deformation of an object. Force is a vector magnitude. Its unit in the International System is the newton (N). The study of forces is fundamental to understanding physical phenomena and describing the behavior of systems in the universe.

Classification of forces in physics

Forces can be classified in different ways depending on the criteria we use. One of the most common ways in physics is to divide them into contact forces and distance forces:

Contact forces

These act when two bodies are in physical contact. Examples: friction, tension in a rope, or the normal force exerted by a surface.

Distance forces

These are exerted without direct contact between bodies. Examples: gravitational force, electric force, and magnetic force.

Another way of classifying forces is according to their origin:

Fundamental forces

These are the four basic interactions of nature: gravitational, electromagnetic, strong nuclear, and weak nuclear.

Derived forces

These arise as a result of the combination of fundamental forces, such as friction or tension.

This classification of forces in physics is key to understanding how objects interact and explaining everyday phenomena such as walking, throwing a ball, or the orbit of the planets.

Types of forces in physics

In the following, we will explore different types of forces and their main characteristics.

Gravitational force

This is the force of attraction between two objects with mass. The gravitational force always acts towards the center of mass of the objects and depends on the mass of the objects and the distance between them, following Newton’s law of universal gravitation.

Electromagnetic force

It is responsible for the interactions between electric charges. This force can be attractive or repulsive and acts through electric and magnetic fields. The electromagnetic force is the basis of phenomena such as friction, magnetic force and interactions between atoms and molecules.

Normal force

It acts perpendicular to the contact surface between two objects and is equal and opposite to the force exerted by the object on the surface.

Frictional force

Arises when there is resistance to relative motion between two surfaces in contact.

Tensile force

Occurs in stretched objects, such as ropes or cables, and acts along them.

Elastic force

This occurs when an elastic body, such as a spring, is deformed and tends to return to its original shape.

The importance of forces in science, technology, and everyday life

The concept of force is one of the pillars of physics because it allows us to explain and predict the movement of bodies. Thanks to its study, humanity has been able to develop everything from Newton’s laws to advanced technologies such as airplanes, automobiles, satellites, and energy systems. In everyday life, forces are present in every action: walking, writing, opening a door, or simply holding an object. Understanding how forces work not only helps us comprehend the natural world, but also facilitates innovations in engineering, medicine, transportation, and virtually all areas of knowledge. Therefore, the importance of forces goes far beyond theory: they are the foundation that connects science with everyday life and the driving force behind much of technological progress.