1. (Sm). Process characterized by manifesting a productive activity in constant change or evolution.
2. (Adj.) Of a person full of vigor who stands out for his ability to influence or change an activity.
3. Physics. (YE). Field of mechanics that studies the influence of forces on motion.
Etymology: By the Greek δυναμική (dynamikḗ), feminine of δυναμικός (dynamikos), regarding δύναμις (dynamis) in the sense of ‘power’, ‘strength’.
Grammatical category: noun fem. / Adjective.
in syllables: di-ná-mi-ca.
Dynamic
Evelyn Maitee Marin
Industrial Engineer, MSc in Physics, and EdD
From the point of view of Physics, dynamics is an area of this science that is responsible for the study of the movement of bodies and the causes that originate it. That is, it is based on mathematical and theoretical models that allow describing and analyzing the evolution of the movement of a body or system over time.
The dynamics can be analyzed from various branches of Physics; Thus, we have the dynamics in accordance with classical mechanics, which is based on Newton’s laws. There is also quantum dynamics, which is based, for example, on Hamiltonian mechanics and equations like Schrödinger’s. Likewise, we find relativistic dynamics, which was developed from Einstein’s postulates to respond to problems that involve movements at speeds close to that of light.
It can be said that, in principle, all these branches of dynamics are an evolution or development that classical dynamics has undergone when it does not offer solutions to particular situations or contexts, or that the answers obtained do not satisfy any physical principle. or does not agree with the experimental findings.
classical dynamic
To understand the mathematical and theoretical foundations of dynamics, it is advisable to start by studying the concepts of classical dynamics. Some of the key elements in this area are defined below:
Force: is the result of the interaction between two or more bodies, and said interaction can be by contact (for example, the normal reaction, tension of a rope or friction force), or at a distance (gravitational force, magnetic force or electric force ). Since classical dynamics analyzes movement and its evolution from the causes that produce it, these causes are associated with forces.
In the interaction by contact, the tension exerted by the rope on the climber is observed, since in order to hold it, it requires physical contact between the person and the rope. In the distance interaction, a magnet is shown, which exerts a magnetic force on objects with ferromagnetic properties without having to touch them.
Free body diagram: it is a graphical representation showing the real external forces acting on a body or system being analyzed. This diagram is a very useful tool when applying Newton’s laws.
The free body diagrams (FBDs) shown to the right indicate the forces acting on the gray box and on the skier.
Inertia: property that bodies have to resist the change of state of motion. This property is directly related to the mass of the object (inertial mass), that is, the greater the mass, the greater the opposition of the body to modifying its state of rest or movement.
Particle: is a geometric point to which a mass is associated. Being represented as a point, it lacks dimensions, so that the forces applied to a particle will always be concurrent, and also, the only movement they can undergo is translation.
Newton’s laws
Isaac Newton was a mathematician and physicist of English origin, born in 1642 and considered the father of classical mechanics, whose laws were published by Newton in 1687 in a work entitled Mathematical principles of natural philosophyand even today, they continue to offer acceptable results for a large number of phenomena that involve movements at speeds well below the speed of light, for example, a vehicle, a person walking, an airplane, etc.
Newton’s First Law
This law is known as the law of inertia, and states that all bodies will remain in their state of rest, or motion at constant speed, unless they are acted on by an unbalanced external force that forces them to change their condition of rest or motion.
From the physical point of view, if when analyzing a particle it is observed that it is in equilibrium (either static or dynamic), it is concluded that the sum of the external forces (called resultant force) is zero; this is:
\(\sum \vec F = \vec 0\) (For a body in equilibrium)
Second law of Newton
When the sum of all the external forces acting on a particle or system is different from zero, said force system is said to be unbalanced, and consequently, the particle accelerates in the direction indicated by the force vector. resulting.
In a simplified way, Newton’s second law states that the magnitude of the acceleration of a particle is directly proportional to the applied resultant force and inversely proportional to its mass, that is:
\(\sum \vec F = m\vec a\) (For a body with acceleration)
Newton’s third law
Also called the law of action and reaction, this law states that whenever a force is applied to a body, another force of equal magnitude and opposite direction is generated as an immediate consequence.
This means that the forces in the universe occur in pairs, that is, for each action, there is always an equal and opposite reaction acting on different bodies.
The force that the person’s fist applies to the piece of paper that is on a surface (\({\vec F_{1/2}}\) in red), is the same force applied to the piece of paper to the person’s fist (\({\vec F_{2/1}}\) in blue), but in the opposite direction.
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