How did newton come up with the laws?

Answer 1

He came up with them by thinking deeply and obsessively. Sir Isaac newton was a genius, perhaps the greatest genius the world has ever known. After inventing the eponymous fig-filled pastry-like cookie -- the Fig Newton -- he yearned for more difficult challenges and turned his attention to physics, writing the Philosophiæ Naturalis Principia Mathematica, a three-volume work published in July, 1687. It contains the statement of Newton's laws of motion and his law of universal gravitation.

Answer 2

one day , isaac newton was sitting below an apple tree. at that time , an apple fall down on his head. then , isaac started thinkin why the apple fell down... and why it didn't go upwards or sideways...!

..and after this he started his researches, and found out about the force of gravity.

thus, he build his theories and laws. |

Answer 3

He "stood on the shoulders of giants", to use his words. Most notably, galileo, who had already developed the principle of relativity, which states that the laws of nature are the same no matter how we look at it. Galileo was also a pioneer in utilizing the scientific method, as opposed to the aristotilean method of argument from first principles that had been used up until that time. Several people in Newton's time were beginning to formalize this early physics work with mathematics, including Kepler who extrapolated from the most accurate data available concerning the motion of the planets and created formulae to explain the data. Newton was the smartest and most successful of these physicists. He encountered some problems he couldn't do and actually invented calculus in order to solve them. His use of calculus enabled him to prove that Kepler's laws could actually be proven from his own laws of motion. Liebnez, the brilliant mathematician and philosopher, also developed calculus at approximately the same time using much better notation, but he didn't apply it to physics the way Newton did. (Newton's notation was poor because he so hated Des Cartes' philosophy that he refused to use cartesian coordinates in his math and physics.)

The bottom line is this: The law of momentum is a formalization of Galileo's principle of relativity.
F=ma is an application of calculus to the formal definition of momentum.
Every action has an equal and opposite reaction is a natural consequence of F=ma.
That's basically how he came up with it.

Gravity was the greater leap. He assumed that the same force that makes small objects fall to the earth also pulls planets toward the sun. He probably came up with that by doing a lot of calculus problems until he noticed the natural consequence of an inverse squared law leads to kepler's laws and it simplifies to the kinematic equations, which stem from his 3 laws, when you are near the earth. I'm not sure if that's how it happened, but it makes sense to me.

The apple thing is a myth.

Answer 4

Newton invented his laws to describe motion.

Answer 5

The answer depends on which laws you are referring to: the laws of motion, universal gravity, cooling, calculus, light (and spectrum).