3.3 ISAAC NEWTON
Isaac Newton (1642-1727)
Born in the same year of Galileo’s death.
Orphan since birth. Newton was born three months
after the death of his father
Grew up with his grandmother.
he was a small child; his said that he could have fit
inside a quart mug (≈ 1.1 litres).
he never married, being highly engrossed in his
studies and work.
At the age of 18, his mother attempted to make a
farmer of him.
In 1661, he was admitted in Trinity College,
Cambridge as a sizar.
He read the books of Copernicus, Kepler & Galileo.
1669, he became a professor of mathematics.
(1670-1672) he taught Optics.
1687, he returned back to mechanics.
1704, back to calculus.
Newton was also a member of the Parliament of
England from 1689 to 1690 and in 1701, but
according to some accounts his only comments were to
complain about a cold draught in the chamber and
request that the window be closed.
In 1696, Newton moved to London to take up the post
of warden of the Royal Mint.
1701, retired from Cambridge.
Newton was made President of the Royal Society in
1703 and an associate of the French Academy of
n April 1705, Queen Anne knighted Newton during
a royal visit to Trinity College, Cambridge.
1717, Newton moved the Pound Sterling de
facto from the silver standard to the gold standard.
Newton died in his sleep in London on 31 March
After his death, Newton's body was discovered to
have had massive amounts of mercury in it.
Mercury poisoning could explain Newton's
eccentricity in late life.
In 1704, developed infinitesimal calculus. (Leibniz 1684)
Newton is generally credited with:
the generalised binomial theorem, valid for any exponent.
He discovered Newton's identities, Newton's method
classified cubic plane curves (polynomials of degree three in
made substantial contributions to the theory of finite differences
was the first to use fractional indices
He approximated partial sums of the harmonic
series by logarithms
was the first to use power series with confidence and to revert
he observed that color is the result of objects
interacting with already-colored light rather than
objects generating the color themselves. This is
known as Newton's theory of color.
Components of visible light
Isaac Newton showed that
by shining white light through
a glass prism it could be
separated back into its
and that a lens and a second
prism could recompose the
multicolored spectrum into
Newton’s color disk
In 1668, he was able to produce
the first reflecting telescope.
It is known as Newtonian
It has many advantages compared
to the refracting telescope.
Universality of gravity
In 1687, returned back to work on Mechanics.
What makes an apple falls down, is responsible for
keeping the moon in orbit.
The moon is always falling toward Earth.
The moon moves forward in space, at the same time.
It constantly, misses the Earth.
More than 200 years later, his ideas were put in
Universal Law of Gravity
F G 2
G 6.67 1011 m 3 / kg.s
• This law works all over the universe.
• G was determined experimentally by Cavendish in 1797-
Newton’s Laws of Motion (1687)
The Law of Inertia:
In the absence of external forces, when viewed from
an inertial reference frame, an object at rest
remains at rest and an object in motion continues in
motion with a constant velocity (that is, with a
constant speed in a straight line).
Newton’s 2nd Law
the acceleration of an object is directly proportional
to the net force acting on it and inversely
proportional to its mass.
Newton’s 3rd Law
If two objects interact, the force F12 exerted by
object 1 on object 2 is equal in magnitude and
opposite in direction to the force F21 exerted by
object 2 on object 1.