Transcript Newtonian Revolution

Newtonian
Newtonian
Revolution
Revolution
January 1643- March 1727
Isaac Newton
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Mathematician
Astronomer
Natural Philosopher
Theologian
Alchemist
Physicist
Great Works:
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Helped in developing differential and
integral Calculus
Generalized binomial theorem
Built first practical reflecting telescope
Developed a theory of colors (Having
to do with the way a prism decomposes
white light into many colors.)
Philosophia
Naturalis
Principia
Mathematica (Mathematical Principals
of Natural Philosophy)
Newton’s Three laws of Motion
1st Law
Every object in a state of
uniform motion tends to
Remain in that state of
motion unless an
external force is applied to
it.
2nd Law
A body of mass m subject
to a force F, undergoes an
acceleration a that has the
same direction as the
force and a magnitude
that is directly
proportional to the force
and inversely
proportional to the mass.
F = ma
3rd Law
For every action,
there is an equal
and opposite
reaction.
Deeper into
The First Law
Every object in a state of uniform
motion tends to remain in that state
of motion unless an external force
is applied to it.
This law means that if
an object is at rest, it
will stay at rest until an
outside force acts on it.
Likewise, when the
object is in motion, it
will stay in motion at a
constant speed and
direction until an
outside force causes a
change.
The image above explains Newton’s First Law in simple
terms
Deeper into the
Second Law
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This law states that when a force effects
an object, the object will accelerate
(change in velocity) in the direction of
the force.
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The acceleration of the object is directly
proportionate to the force. If the force is
two times stronger, the acceleration will
be two times greater.
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The acceleration is inversely
proportional to the mass of the object. If
you are pushing two objects with the
same amount of force, and one object
weighs 5 times the other, it will
accelerate at 1/5 the acceleration of the
other.
A body of mass m subject to a
force F, undergoes an
acceleration a that has the
same direction as the force and
a magnitude that is directly
proportional to the force and
inversely proportional to the
mass. F = ma
F
M
A
Above is a (fairly stupid) visual to help you remember Newton’s
equation
To Find F- Cover F up and you will see M next to A
A- Cover A up and you will see F over M
M- Cover M up and you will see F over A
.
Using Newton’s
Second Law
Acceleration=
Force
Mass
Sample Problem
As the result of a serve, a tennis
ball (mt=58g) accelerates at
430 m/s^2 for a very brief
time in contact with the
racket.
A= 430 m/s^2
M= 58g (=0.058kg)
F= ma
*1 Newton= 1kg x m/s²
F= (.058kg)(430m/s^2)
Photograph by The Library of Congress, 1913
For this reason, the Force=24.94 N
Deeper into the
Third Law
For every action, there is an
equal and opposite reaction.
• In any interaction, there is a
pair of forces acting on both
objects.
• The size of the forces on both
objects are equal.
• The direction of the force on the
second object is always
opposite to the direction of the
force on the first.
Forces come in Pears!
An Example of Newton’s
Third Law
Action Reaction
Force Pairs
A fish uses its fins to swim through water by pushing water backwards.
However, this force is matched by the water back to the fish. The
water reacting to the force of the fish, then propels the fish forward in
the water. This is an example of an Action Reaction Force Pair in
nature.
Another look at
Newton’s Third Law
Fa on b= -Fb on a
This equation shows how the
Force from a, on b is equal
to the negative (or opposite)
Force of b on a
It is said that Newton’s thoughts about motion
and gravity were set into action after an apple
fell on his head.
Newton knew that the apple had fallen
straight to the earth because the earth
attracted it. He wondered, could that
gravity also be the force that attracts
the planets to the sun?
According to his third law, the apple
would have to attract the earth just
like the earth attracted the apple. The
force of attraction must also be
proportional to the mass of the earth
This attractive force which
exists between all objects is
Gravitational Force
Newton’s Universal law of Gravitation
F= G
Ma Mb
d2
•D= Distance between centers of the masses
•G= Universal Constant When Ma and Mb are measured in
kilograms, d in meters and F in newtons, then:
-11
2
G= 6.67x10 Nxm /kg
2
Photographs
(Sources)
Tennis: The Library of Congress
Fish: clkr.com, by: Ocal
Pears: Zazzle.ca, by: Doonidesigns
Force image: Brock Physics
Gravitational Force: astronomy.nmsu.edu/