Tuesday, 3 March 2015

Newtons Law Of Gravitation


Gravitation is the force of mutual attraction experienced bodies by having a certain mass. The existence of this force was established by the English mathematician and physicist Isaac Newton in s. XVII, who also developed to its formulation called calculus of fluxions (what today is known as integral calculus).

Isaac Newton was born on December 25, 1642, in Woolsthorpe, Lincolnshire. When he was three, his widowed mother remarried and left him in the care of his grandmother. The widowed a second time, he decided to send him to a primary school in Grantham. In the summer of 1661 he entered Trinity College, University of Cambridge, where he received his title of professor.

During that time he devoted himself to the study and research of the latest advances in mathematics and natural philosophy. Almost immediately, he made fundamental discoveries that were very useful in his scientific career. He also discovered the theory of light and optics, formulated the laws of motion and deduced from them the law of universal gravitation.

The law formulated by Newton and called the law of universal gravitation states that the force of attraction experienced by two bodies endowed with mass is directly proportional to the product of their masses and opposite to the square of the distance between them ( law of inverse square of the distance). The law includes a proportionality constant (G) is called the constant of gravitation and whose value, determined by very precise experiments, is:

6,670. 10-11 Nm² / kg².

To determine the gravitational field associated with a body with a radius and a certain mass, the acceleration with which a body falls Test (radio and mass unit) within this field is set. By applying Newton's second law taking the values of the force of gravity and a known mass, one can obtain the acceleration of gravity.
Such acceleration has different values depending on the body on which it is measured; so, for the earth is considered a value of 9.8 m / s (equivalent to 9.8 N / kg), while the value obtained for the surface of the moon is only 1.6 m / s², ie about six times lower than that for our planet, and one of the giant planets of the solar system, Jupiter, this value would be about 24.9 m / s².

In an isolated system consisting of two bodies, one of which rotates around the other, with the former having a much smaller than the second mass and describing a stable circular orbit around the body that occupies the center, centrifugal force has a value equal to the centripetal due to the existence of universal gravitation.

From considerations such as this one can deduce Kepler's laws (the third), which relates the radius of the orbit described a body around another center, with the time it takes to sweep the area that encloses this orbit, and states that time is proportional to 3/2 of the radius. This result is of universal application and is also true for the elliptical orbits, of which circular orbit is a special case in which the major and minor semiaxes are equal.

Blaise Pascal - Biography



PortraitAm June 19, 1623 is Blaise Pascal, the son of Étienne Pascal, higher tax official of Clermont (1588-1651) and Antoinette Pascal, born Begon (1596-1626), Clermont (Auvergne), Rue des Gras born. He was baptized on 27 June.

He has two sisters: Gilberte (1620-1687) and Jacqueline (1625-1661), who take both major influence on the development of Pascal. At an early age makes itself at Blaise Pascal extremely fragile physical condition noticeable.


Blaise Pascal's mother died in 1626. Pascal's father buys the Office of the second President of the Cour des Aides (Tax Court) for 31600 livres.

The father leaves 1631 Clermont-Ferrand and settled with his three children (born in 1625 by Jacqueline) to Paris, but retains his office.
He teaches his children according to the methods of education with a focus on Montaigne's ancient languages. The father comes in close contact with both literary and scientific and philosophical elites.

Blaise Pascal developed in this intellectual atmosphere to Pascal's birthplace A mathematical 'wunderkind', although he initially following the example of Montaigne, instructed by his father only in the ancient languages. About the methodical and deliberate actions of the father's sister reported:

"It was his guiding principle for this education, always make sure that this child was superior to his work, and that's why he did not want to teach him the Latin language before the twelfth year, so he will learn more easily.
But he let him now not idle because he taught him all things which he found him capable. He generally showed him the nature of language; He showed him how they had been attributed to certain grammatical rules; that these rules have exceptions that you have carefully designated; and that they had found a way in this manner, notify all languages from country to country. This general idea brought order into his mind and showed him the reason for the rules of grammar; and so he did, as he then learned why he did it, and turned his attention very things that demanded the most attention. "

His natural talent shows, inter alia, that he the first 32 sets of Euclidean geometry derived independently as a child. Early on, he participates in the meetings of the "Académie Mersenne," one of the previous sections of the "Académie des sciences". There he met, among others René Descartes know.

But not only Blaise turns out to be a child prodigy, his sister Jacqueline has a special talent. She writes even as a 12 year old verses that can recognize extraordinary poetic talent.
1638 father, who had protested against a financial regulation must leave Paris and flees into the province, in the Auvergne, in order to escape the Bastille.
Jacqueline, after playing in front of Cardinal Richelieu, the most powerful man in France, a role in a comedy of Madame de Scudéry 'Le prince déguisé', to implore and receive the pardon of her father. This is sent by the king in 1639 as the authorized Commissioner for the place in ClermontSteuerwesen to Rouen. He assists the Registrar Séguier 1640 at the bloody suppression of a riot.

Blaise Pascal's 1640 first work printed 'Essai sur les coniques' (Treatise on Conic Sections). This mathematical feat makes him who is just 16 years old, suddenly in the scientific world known.


1633 Saint-Cyran is - in fact you called Jean de Vergier Hauranne (1581-1643) as a preacher and confessor in the important Parisian convent Port-Royal.
He is a friend of Cornelius Jansen (1585-1638), author of 'Augustine' and the namesake of the church reform movement of Jansenism.

To the monastery numerous Parisian bourgeois families, including the famous Arnauld family will gather.