Second law of Newton


Newton’s laws are a series of laws that are also known as Newton’s laws of motion . In these laws are three principles from which it was possible to give an explanation to a large number of the problems that had been raised in the field of classical mechanics , mainly those that were related to the movement of bodies , laws that achieved revolutionize the basic concepts of physics and the movement of bodies in the universe.


What is Newton’s second law?

The Newton ‘s second law states that when a body exerts a force on a second body , the second makes force on the first whose magnitude is the same, but it ‘s going in the opposite direction to the first.

  • What is Newton’s second law?
  • What is your name
  • Who proposed it
  • History
  • Statement
  • Characteristics of Newton’s second law
  • Formula
  • Target
  • Explanation
  • Applications of Newton’s Second Law
  • Experiments
  • Examples
  • Conclution

What is Newton’s second law?

The second law consists in the explanation of what happens if a net force acts on a body that is in motion and whose mass does not have to be constant, which is capable of modifying the state of motion , generating a change in the speed or direction . The changes that are experienced in the momentum of a body are proportional to the motive force and at the same time develop in the direction of this. Consequently, there is a relationship between cause and effect , between force and acceleration since they are related.


What is your name

Newton’s second law or law of force is also known as the  fundamental law of dynamics.

Who proposed it

Newton’s second law was proposed by Sir Isaac Newton , an important and renowned English mathematician and physicist who managed to stand out as the most representative figure of the 17th century “Scientific Revolution” . In his studies on mechanics , he created the three laws of motion, better known as “Newton’s laws” , and these are considered today as the basic principles of modern physics .


The mathematical formulation was made and published by Isaac Newton in 1687, in his work Philosophiae Naturalis Principia Mathematica. In the third volume of Newton’s work, he himself succeeded in showing that, by combining the laws with his law of universal gravitation, Kepler’s Laws of planetary motion can be deduced and explained .


The original statement reads as follows:

” Change in motion is proportional to the motive force impressed; and is made in straights where the force is impressed. “

Translated into Spanish, it says the following: the change in motion is directly proportional to the printed motive force and occurs according to the straight line along which that force is printed.

Characteristics of Newton’s second law

The most representative characteristics of Newton’s second law are the following:

  • In the bodies that participate there are forces that are related by means of the law of action and reaction .
  • The second law is one of the basic laws of mechanics.
  • When there are cases in which the mass is not constant, the formula of the second law can vary.


The acceleration that a body of mass “m” acquires, under the action of a force “F”, is directly proportional to the force “F” and inversely proportional to the mass “m”.

a = F / m


The objective that Newton’s second law seeks is to determine the relationship that exists between the force , mass and acceleration of a body that is in unidirectional motion , and that is under the action of a net external force . Another objective is to verify the theory that tells us that force is equal to the compliance mass by the acceleration .


Newton’s second law has the function of quantifying the concept of force . It explains that the net force that is applied on a body is proportional to the acceleration that the body acquires. This law explains what happens if a net force acts on a body that is in motion, causing a change in the state of motion and changing the speed .

Applications of Newton’s Second Law

The applications of this law are many and we can find it in fields of study, such as medicine , zoology , geology , physics , chemistry or engineering . In the area of ​​medicine, mainly in traumatology , it is very useful to be able to know the forces to which we submit to our bones. In zoology , we can determine the force of an animal’s bite by measuring the acceleration suffered by an object that is put in the animal’s mouth to bite it. If we know the force that the engine exerts on a carto advance we can also know the value of the acceleration of the car itself through Newton’s second law.


The simplest experiment to do is to push an object and measure the force that has been applied and then analyze its acceleration . It can be done by placing a scale between your hands and the object to be pushed. The measurement given by the scale is the force in kilos applied to the object.

Using a cart of toy applies a force to go ahead, that is, it pushes and half of his career push it again to double the speed but so to continue his career.


Some examples that we can mention about Newton’s second law are:

  • The speed a rocket needs to get into orbit is another example.
  • The calculation of the acceleration of a stone in free fall reflects Newton’s claim.
  • The speed that a rocket needs to be able to get into orbit is another example.
  • The force that must be exerted on a car for this advance is another example of Newton’s second law.
  • The strength that a cart must have to be able to transport its load.


In conclusion we can say that Newton’s second law is one of the most basic laws in the area of mechanics , which is used to analyze the movements closest to the surface of the earth and also participates in the study of celestial bodies. .

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