Understanding Newton's First Law of Motion

The first law deals with forces and changes in velocity. For just a moment, let us imagine that you can apply only one force to an object.

That is, you could choose push the object to the right or you could choose to push it to the left, but not to the left and right at the same time, and also not up and to the right at the same time, and so on.

For every action, there is an equal and opposite reaction.

Firstly, it accelerates in the direction you push it.

Secondly,if you push twice as hard, it accelerates twice as much.

Thirdly,if you push on it, it pushes on you.

1) Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it.

2) Force is equal to the change in momentum per change in time. For a constant mass, force equals mass times acceleration.

3) For every action, there is an equal and opposite reaction.

› It is important to note that these three laws together with his Law of Gravitation provide a satisfactory basis for the explanation of motion of everyday macroscopic objects under everyday conditions.

› However, when applied to extremely high speeds or extremely small objects, Newton's Laws break down; this was remedied by Albert Einstein's Special theory of Relativity for high speeds and by Quantum Mechanics for small objects.

He was an English physicist, mathematician, astronomer, natural philosopher, alchemist, theologian and one of the most influential men in human history.

Sir Isaac Newton was born on January 4, 1643 at Woolsthorpe Manor in Woolsthorpe-by- Colsterworth , a hamlet in the county of Lincolnshire. At the time of Newton's birth, England had not adopted the latest papal calendar and therefore his date of birth was recorded as Christmas Day, 25 December 1642. Newton was born prematurely, he was a small child; three months after his father’s death.

(1643-1727]

In 1679, Newton returned to his work on mechanics, gravitation

and its effect on the orbits of planets, with reference to Kepler's

Laws of Planetary Motion.

Newton's reawakening interest in astronomical matters received

further stimulus by the appearance of a comet in the winter of

1680/1681.

Newton worked out a proof that the

elliptical form of planetary orbits would result from a centripetal

force inversely proportional to the square of the radius vector .

Mechanics& Gravitation

Quote: “We build too many walls and not enough bridges.”

-Isaac Newton