We explain what dynamics is and what the fundamental laws of dynamics are. History of discovery, and related principles.
What is Dynamics?
Dynamics is the part of physics that studies the relationship between the forces acting on a body and the effects that will occur on the movement of that body.
Ancient Greek thinkers believed that the speed and constancy of motion in a straight line of a body (a phenomenon described years later as uniform rectilinear motion or MRU) were proportionally related to a constant force. By extension, the fall of a body was believed to belong to that category, so it was supposed to the body that weighed the most would fall faster.
Later, Galileo Galilei understood that the fall of bodies could not be a uniform movement, and that From the same height, two bodies of different weight take the same time to fall. This context was what made it possible for some years later, Isaac Newton to establish the three fundamental laws of dynamics, which explained the fundamental patterns of the behavior of bodies.
See also: Kinematics
Newton's laws
- The principle of inertia. It indicates that when a body is at rest, or describes a movement with the characteristics of MRU, the forces applied to it have a zero resultant. You have to be very careful in this case, since they are influenced, for example, by the force of friction. When the forces are truly balanced, the MRU can truly occur.
- Force is equal to mass times acceleration. This is the fundamental formula of dynamics, and it comes from assuming a body at rest on a horizontal surface, which is subject to a force parallel to that surface, being able to dispense with friction: we will see that the body is set in motion at a constant acceleration. If another force of greater intensity is applied, the acceleration will vary proportionally.
In this way, this formula is reached, and the international unit of force can be established, the Newton (N), defined as the force that propels a mass of one kilogram with an acceleration of one meter per second squared. - Law of action and reaction. Whenever one body exerts a force on another, this second exerts an opposite force of equal intensity and direction but opposite direction on the first. The first example is that of a body that weighs on a surface, which will receive from it the action of a force that opposes the attraction that the earth exerts on it.
These laws are the fundamental laws of dynamics, which apply fundamentally to uniform rectilinear motion. However, also there is a dynamics of circular motionwhich happens when the force applied to a body can be maintained constantly in modulus, perpendicular to the direction of movement. This occurs, for example, in the case of the constant force of attraction of the Sun on a planet, which prevents it from exercising a rectilinear movement instead of orbit.
However, There is also the analysis of the behaviors of the bodies when various particles intervene, in addition to the aforementioned forces. The part of physics that uses statistical methods to study the global behavior of systems is thermodynamics.
It has a series of principles, among which we can mention thermal balance, that is, equality between the heat received and that emitted by the body, achieved through heat exchange. Also It is said that energy is neither produced nor destroyedbut rather it is transformed, making the production of work impossible without the consumption of energy, and from this it arises that heat cannot be completely transformed into work, there always being a loss.
There is also a colloquial use of the term, which It is applied to speak symbolically of things that are in motion. You can talk about the dynamics of political processes, public events or anything, to refer to 'how it developed' over a period of time. Also, it is used as an adjective to talk about people who are very restless and who spend much of their time moving.
