Newtonian Revolution Isaac Newton January 1643- March 1727 Mathematician Astronomer Natural...
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Transcript of Newtonian Revolution Isaac Newton January 1643- March 1727 Mathematician Astronomer Natural...
Newtonian Revolution Newtonian Revolution
Isaac Newton January 1643- March 1727
• Mathematician• Astronomer• Natural Philosopher• Theologian• Alchemist• Physicist
Great Works: 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 LawA 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 LawFor 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• This law states that when a force effects
an object, the object will accelerate (change in velocity) in the direction of the force.
• 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.
• 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 LawSample 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)
For this reason, the Force=24.94 N
Acceleration=
Force Mass
Photograph by The Library of Congress, 1913
Deeper into the Third Law
• 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.
For every action, there is an equal and opposite reaction.
Forces come in Pears!
An Example of Newton’s
Third Law
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.
Action Reaction Force Pairs
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:
G= 6.67x10 Nxm /kg -11 2 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/