This document provides an overview of Isaac Newton's laws of motion and summarizes Newton's three laws. It introduces Newton as the physicist who formulated the laws of motion. Newton's three laws are then defined: the first law states that an object remains at rest or in uniform motion unless acted upon by an external force; the second law relates force, mass, and acceleration; and the third law states that for every action there is an equal and opposite reaction. Examples are given to illustrate each law, such as how inertia causes a rocket ship to maintain its trajectory in space without gravity or friction, and how pushing against a wall causes one to slide away due to the wall exerting an equal and opposite force.
4. SIR ISSAC NEWTON ( 25 December 1642 – 20 March
1726) was an English physicist and mathematician who
is widely recognised as one of the most influential
scientists of all time and as a key figure in the
scientific revolution.
Newton's Principia formulated the laws of motion and
universal gravitation, which dominated scientists' view
of the physical universe for the next three centuries.
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6. Newton's laws of
motion
Newton's laws of motion are three physical laws that
together laid the foundation for classical mechanics.
They describe the relationship between a body and the
forces acting upon it, and its motion in response to said
forces.
The three laws of motion were first compiled by Isaac
Newton in his Philosophiæ Naturalis Principia
Mathematica (Mathematical Principles of Natural
Philosophy), first published in 1687.Newton used them
to explain and investigate the motion of many physical
objects and systems. 6
7. THE THREE LAWS
First Law- 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.”
Second law- “Force is equal to the change in
momentum(mV)per change in time. For a constant mass,
force equals mass times acceleration”
F = ma
Third law- “For every action , there is an equal and
opposite re-action”
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9. THE F I R S T L A W
Newton's first law of motion states that every object will
remain at rest or in uniform motion in a straight line
unless compelled to change its state by the action of an
external force. This is normally taken as the definition
of inertia. The key point here is that if there is no net
force acting on an object (if all the external forces cancel
each other out) then the object will maintain a constant
velocity. If that velocity is zero, then the object remains
at rest. If an external force is applied, the velocity will
change because of the force. 9
10. WHAT DOES 1ST LAW MEAN
???
Basically, an object will “keep doing what it was
doing” unless acted on by an unbalanced force.
If the object was sitting still, it will remain
stationary. If it was moving at a constant velocity,
it will keep moving.
It takes force to change the motion of an object.
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11. In outer space, away from gravity and
any sources of friction, a rocket ship
launched with a certain speed and
direction would keep going in that
same direction and at that same speed
forever.
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12. THE SECOND LAW
The second law explains how the velocity of an object changes
when it is subjected to an external force. The law defines a force
to be equal to change in momentum (mass times velocity) per
change in time. Newton also developed the calculus of
mathematics, and the "changes" expressed in the second law are
most accurately defined in differential forms. (Calculus can also be
used to determine the velocity and location variations
experienced by an object subjected to an external force.) For an
object with a constant mass m, the second law states that the force
F is the product of an object's mass and its acceleration a:
F = m * a
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13. WHAT DOES 'F=M*A'
MEANlForce is directly proportional to mass and acceleration.
Imagine a ball of a certain mass moving at a certain
acceleration. This ball has a certain force.
lNow imagine we make the ball twice as big (double the
mass) but keep the acceleration constant. F = ma says
that this new ball has twice the force of the old ball.
lNow imagine the original ball moving at twice the original
acceleration. F = ma says that the ball will again have
twice the force of the ball at the original acceleration.
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14. WHAT DOES F=ma SAY
???????
F = ma basically means that the force of an object
comes from its mass and its acceleration.
Something very massive (high
mass) that’s changing speed
very slowly (low acceleration),
like a glacier, can still have great
force. Something very small (low mass)
that’s changing speed very quickly
(high acceleration), like a bullet, can
still have a great force. Something
very small changing speed very slowly
will have a very weak force.
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15. THE THIRD LAW
For every action there is an equal and
opposite reaction.
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16. What does this mean?
For every force acting on an object, there is an equal
force acting in the opposite direction. Right now,
gravity is pulling you down in your seat, but
Newton’s Third Law says your seat is pushing up
against you with equal force. This is why you are
not moving. There is a balanced force acting on
you– gravity pulling down, your seat pushing up.
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17. What happens if you are standing on
a skateboard or a slippery floor and
push against a wall? You slide in the
opposite direction (away from the
wall), because you pushed on the wall
but the wall pushed back on you with
equal and opposite force.
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