need help with information about Isaac Newton and how he found gravity

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http://www.light-science.com/newtonapple.html

thanks. i need more information about Isaac Newton and his 'apple'.

http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html

http://en.wikipedia.org/wiki/Isaac_Newton

http://gardenofpraise.com/ibdnewt.htm

http://encarta.msn.com/encyclopedia_761573959/Isaac_Newton.html

Isaac Newton, one of the most influential physicists and mathematicians in history, made significant contributions to our understanding of gravity. His groundbreaking work laid the foundation for classical physics and the laws of motion. Let's explore how Newton arrived at his theory of gravity.

1. Observations: Newton first observed the motion of objects falling to the ground and the motion of planets in the sky. He noticed that all objects, regardless of their size or composition, fall towards the Earth with the same acceleration.

2. Inverse Square Law: After gathering data and conducting experiments, Newton proposed that the force of gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. This proposition is known as the "inverse square law."

3. Calculating the Gravitational Constant: Newton realized that he needed to determine the gravitational constant, which quantifies the strength of gravity. By using mathematical techniques, including calculus, he formulated equations and developed a method to calculate the gravitational constant.

4. Principia Mathematica: Newton compiled his findings, calculations, and theories into a book called "Philosophiæ Naturalis Principia Mathematica" (Mathematical Principles of Natural Philosophy), commonly known as "Principia." In this work, he described the laws of motion, the law of universal gravitation, and various mathematical techniques he used.

5. Law of Universal Gravitation: Newton's law of universal gravitation states that every particle attracts every other particle in the universe with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

It's important to note that Newton's discovery of gravity built upon the foundation laid by other scientists, such as Galileo Galilei and Johannes Kepler. Newton's contribution was his combination of mathematical principles, empirical observations, and precise calculations, which led to the formulation of a comprehensive theory of gravity.