Transcript The Limits of Kepler`s Laws

The Limits
of Kepler’s
Laws
Kepler’s laws allowed
the relative size of
the solar system to
be calculated, but
not the actual size.
This could not be
calculated until the
invention of radar,
which could be used
to find the distance
to Venus.
Adding these two
distances, the
astronomical unit
is defined as
8
1.5 x 10 km.
Kepler’s laws
told how the
planets move,
but not why.
Isaac Newton
(1642-1727) was
born in Lincolnshire,
England on Christmas
Day in 1642,
the year Galileo died.
Newton studied at
Cambridge, but the
arrival of the bubonic
plague forced him
home for two years.
He went to live on
his uncle’s farm.
It was there he
made one of his
most famous
discoveries, the
Law of Gravity.
For some reason he didn’t tell
anyone for 20 years, until he
offhandedly mentioned it to
Edmund Halley in 1684. Halley
encouraged Newton to publish
his work, and he did so in a
work known as Newton’s
Principia.
Newton’s three Laws
of Motion, the Law of
Gravity, and the calculus
are adequate to explain all
motion we see here on
Earth and throughout the
universe.
Newton’s First Law of Motion objects resist acceleration.
(Inertia)
Newton’s Second Law of Motion
F = ma
Newton’s Third Law
of Motion - To every
action there is an
equal and opposite
reaction.
The Law of Universal Gravitation Every particle of matter in the
universe attracts every other
particle with a force that is directly
proportional to the product of the
masses and inversely proportional
to the square of the distance
between them.
Galileo realized the concept
of inertia (which conflicted
with Aristotle’s belief that the
natural state of an object was
to remain at rest) long before
Newton came up with his first
law.
Galileo’s famous
inclined plane
experiments led him to
the logical extension of
having no second
plane at all.
Newton’s laws
describe the
way forces
affect motion.
Force - a physical
quantity that can
affect the state of
motion of an object.
(a “push” or “pull” on
an object)
There are two
general types of
forces: contact
forces and field
forces.
Forces on an object
can be depicted with
a force diagram
(free-body diagram).
The unit of force is the
newton: one newton
is the force needed to
accelerate a one kilogram
mass by one meter per
second per second.
NEWTON’S
FIRST
LAW:
If there is no net force
acting on a body, it will
continue in its state of
rest or will continue
moving along a straight
line with constant
speed.
LAW OF
INERTIA