Transcript "the law of inertia".

Sir Isaac Newton was one of the greatest scientists and mathematicians that ever
lived. He was born in England on December 25, 1643. He was born the same year that
Galileo died. He lived for 85 years.
Isaac Newton was raised by his grandmother. He attended Free Grammar School and
then went on to Trinity College Cambridge. Newton worked his way through college.
While at college he became interested in math, physics, and astronomy. Newton
received both a bachelors and masters degree.
While Newton was in college he was writing his ideas in a journal. Newton had new
ideas about motion, which he called his three laws of motion. He also had ideas about
gravity, the diffraction of light, and forces. Newton's ideas were so good that Queen
Anne knighted him in 1705. His accomplishments laid the foundations for modern
science and revolutionized the world. Sir Isaac Newton died in 1727.
In this lesson you will develop an understanding of each of Newton's Three Laws of
Motion.
First Law of Motion
According to Newton's first law...
An object at rest will remain at rest unless
acted on by an unbalanced force. An
object in motion continues in motion with
the same speed and in the same direction
unless acted upon by an unbalanced
force.
This law is often called
"the law of inertia".
What does this mean?
This means that there is a natural tendency of
objects to keep on doing what they're doing. All objects
resist changes in their state of motion. In the absence
of an unbalanced force, an object in motion will
maintain this state of motion.
Let's study the "skater" to understand this a little better.
What is the motion in this picture?
What is the unbalanced force in this picture?
What happened to the skater in this picture?
This law is the same reason why you should
always wear your seatbelt.
Acceleration is produced when a force
acts on a mass. The greater the mass (of
the object being accelerated) the greater
the amount of force needed (to accelerate
the object).
What does this mean?
Everyone unconsciously knows
the Second Law. Everyone knows
that heavier objects require more
force to move the same distance
as lighter objects.
However, the Second Law gives us an exact
relationship between force, mass, and
acceleration. It can be expressed as a
mathematical equation:
or
FORCE = MASS times ACCELERATION
This is an example of how Newton's Second Law
works:
Mike's car, which weighs 1,000 kg, is out of gas. Mike is trying
to push the car to a gas station, and he makes the car go
0.05 m/s/s. Using Newton's Second Law, you can compute
how much force Mike is applying to the car.
Answer = 50 newtons
For every action
there is an equal and
opposite re-action.
What does this mean?
This means that for every
force there is a reaction
force that is equal in size,
but opposite in direction.
That is to say that whenever
an object pushes another
object it gets pushed back in
the opposite direction
equally hard
Let's study how a rocket
works to understand
Newton's Third Law.
The rocket's action is to push
down on the ground with the
force of its powerful engines,
and the reaction is that the
ground pushes the rocket
upwards with an equal force.
UP,
UP,
and
AWAY!
You have just learned
about
Newton's Three Laws
of Motion.
A magician pulls a tablecloth out
from under dishes and glasses on a
table without disturbing them.
According to Newton's first law...
An object at rest will remain at rest unless
acted on by an unbalanced force. An
object in motion continues in motion with
the same speed and in the same direction
unless acted upon by an unbalanced
force.
This law is often called
"the law of inertia".
A person’s body is thrown
outward as a car rounds a
curve on a highway.
According to Newton's first law...
An object at rest will remain at rest unless
acted on by an unbalanced force. An
object in motion continues in motion with
the same speed and in the same direction
unless acted upon by an unbalanced
force.
This law is often called
"the law of inertia".
Rockets are launched into
space using jet propulsion
where exhaust
accelerates out from the
rocket and the rocket
accelerates in an opposite
direction.
For every action
there is an equal and
opposite re-action.
What does this mean?
This means that for every
force there is a reaction
force that is equal in size,
but opposite in direction.
That is to say that whenever
an object pushes another
object it gets pushed back in
the opposite direction
equally hard
A picture is hanging
on a wall and does
not move.
According to Newton's first law...
An object at rest will remain at rest unless
acted on by an unbalanced force. An
object in motion continues in motion with
the same speed and in the same direction
unless acted upon by an unbalanced
force.
This law is often called
"the law of inertia".
A person not wearing a
seatbelt flies through a
car window when
someone slams on the
breaks because the
person’s body wants to
remain in continuous
motion even when the
car stops.
According to Newton's first law...
An object at rest will remain at rest unless
acted on by an unbalanced force. An
object in motion continues in motion with
the same speed and in the same direction
unless acted upon by an unbalanced
force.
This law is often called
"the law of inertia".
Pushing a child on
a swing is easier
than pushing an
adult on the same
swing, because
the adult has more
inertia.
Acceleration is produced when a force
acts on a mass. The greater the mass (of
the object being accelerated) the greater
the amount of force needed (to accelerate
the object).
What does this mean?
Everyone unconsciously knows
the Second Law. Everyone knows
that heavier objects require more
force to move the same distance
as lighter objects.
A soccer ball
accelerates more
than a bowling ball
when thrown with
the same force.
Acceleration is produced when a force
acts on a mass. The greater the mass (of
the object being accelerated) the greater
the amount of force needed (to accelerate
the object).
What does this mean?
Everyone unconsciously knows
the Second Law. Everyone knows
that heavier objects require more
force to move the same distance
as lighter objects.
A soccer
player kicks a
ball with their
foot and their
toes are left
stinging.
Acceleration is produced when a force
acts on a mass. The greater the mass (of
the object being accelerated) the greater
the amount of force needed (to accelerate
the object).
What does this mean?
Everyone unconsciously knows
the Second Law. Everyone knows
that heavier objects require more
force to move the same distance
as lighter objects.
A student leaves
a pencil on a
desk and the
pencil stays in
the same spot
until another
student picks it
up.
According to Newton's first law...
An object at rest will remain at rest unless
acted on by an unbalanced force. An
object in motion continues in motion with
the same speed and in the same direction
unless acted upon by an unbalanced
force.
This law is often called
"the law of inertia".
Two students are in a
baseball game. The first
student hits a ball very
hard and it has a greater
acceleration than the
second student who bunts
the ball lightly.
Acceleration is produced when a force
acts on a mass. The greater the mass (of
the object being accelerated) the greater
the amount of force needed (to accelerate
the object).
What does this mean?
Everyone unconsciously knows
the Second Law. Everyone knows
that heavier objects require more
force to move the same distance
as lighter objects.
1. Who was the scientist who gave us the Laws of Motion?
2. How many Laws of Motion are there?
3. What is another name for the first law of motion?
4. Which law explains why we need to wear seatbelts?
5. Which law says that force is equal to mass times acceleration
(F=MA)?
6. Which law says that heavier objects require more force than
lighter objects to move or accelerate them?
7. Which law explains how rockets are launched into space?
8. Which law says that for every action there is an equal and opposite
reaction?
1. Who was the scientist who gave us the Laws of Motion?
Answer: Sir Isaac Newton
2. How many Laws of Motion are there?
Answer: three
3. What is another name for the first law of motion?
Answer: Law of Inertia
4. Which law explains why we need to wear seat belts?
Answer: First Law of Motion
5. Which law says that force is equal to mass times acceleration
(F=MA)?
Answer: Second Law of Motion
6. Which law says that heavier objects require more force than lighter
objects to move or accelerate them?
Answer: Second Law of Motion
7. Which law explains how rockets are launched into space?
Answer: Third Law of Motion
8. Which law says that for every action there is an equal and opposite
reaction?
Answer: Third Law of Motion