Leyes de newton en relacion a satelites

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  • Publicado : 17 de mayo de 2010
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"Un cuerpo mantiene un movimiento uniforme a menos que una fuerza actúe sobre él"

Por eso los satélites orbitan por encima de la atmósfera terrestre, pues así la fuerza de rozamiento no reduce su velocidad y por tanto aumenta el tiempo que el satélite se mantiene en órbita.



Esta no afecta en la órbita, pues la fuerza de atracción terrestre sobre el satélitees Fg=G * (M/m) / (r^2) donde M es la masa de la Tierra y m la del satélite. Si igualamos nos queda: G * (M/m) / (r^2) = m * a , luego podemos dejarlo como a = G * M / (r^2). Esta es la razón de que dos objetos caigan al mismo tiempo independientemente de su masa (si no hubiera rozamiento con el aire)

Durante el lanzamiento sí afecta, puesto que F = m * a -> a = F/m, luego si queremos lanzardos satélites de distinta masa con una misma aceleración, el lanzador del satélite más pesado debe ser más potente (debe aumentar F)

Añado que la tercera ley de Newton "Toda fuerza tiene una igual pero en sentido inverso" también afecta pues el principio en que se basan los cohetes al igual que los motores a reacción.

A rocket in its simplest form is a chamber enclosing a gas under pressure. A small opening at one end of the chamber allows the gas to escape, and in doing so provides a thrust that propels in the opposite direction. A good example of this is a balloon. Air inside a balloon is compressed by the balloon's rubber walls. The air pushes back so that theinward and outward pressing forces are balanced. When the nozzle is released, air escapes through it and the balloon is propelled in the opposite direction. 
When we think of rockets, we rarely think of balloons. Instead, our attention is drawn to the giant vehicles that carry satellites into orbit and spacecraft to the Moon and planets. Nevertheless, there is a strong similarity between the two.The only significant difference is the way the pressurized gas is produced. With space rockets, the gas is produced by burning propellants that can be solid or liquid in form or a combination of the two.
One of the interesting facts about the historical development of rockets is that while rockets and rocket-powered devices have been in use for more than two thousand years, it has been only inthe last three hundred years that experimenters have had a scientific basis for understanding how they work.
The science of rocketry began with the publishing of a book in 1687 by the great English scientist Sir Isaac Newton. His book, entitled Philosophiae Naturalis Principia Mathematica, described physical principles in nature. Today, Newton's work is usually just called the Principia. In thePrincipia, Newton stated three important scientific principles that govern the motion of all objects, whether on Earth or in space. Knowing these principles, now called Newton's Laws of Motion, rocketeers have been able to construct the modern giant rockets of the 20th century such as the Saturn V and the Space Shuttle. Here now, in simple form, are Newton's Laws of Motion. 
1. Objects at restwill stay at rest and objects in motion will stay in motion in a straight line unless acted upon by an unbalanced force. 
2. Force is equal to mass times acceleration. 
3. For every action there is always an opposite and equal reaction. 
As will be explained shortly, all three laws are really simple statements of how things move. But with them, precise determinations of rocket performancecan be made. 
Newton's First Law
This law of motion is just an obvious statement of fact, but to know what it means, it is necessary to understand the terms rest, motion, and unbalanced force.
Rest and motion can be thought of as being opposite to each other. Rest is the state of an object when it is not changing position in relation to its surroundings. If you are sitting still in a chair,...
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