Transcript Newton`s Laws of Motion

• 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.
• Newton attended Trinity College
Cambridge where he became
interested in math, physics, and
astronomy.
• Newton had new ideas about
motion, which he called his three
laws of motion.
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".
Inertia: the tendency of all objects to
resist any change in motion.
Let’s break it down
An object at rest will remain at rest
unless acted on by an unbalanced
force.
What does at rest mean?
Let’s break it down
An object in motion continues in motion
with the same speed and in the same
direction unless acted upon by an
unbalanced force.
Why do objects set in motion stop?
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?
Is there evidence of inertia?
This law is the same reason why you
should always wear your seatbelt.
What is the motion in this picture?
What is the unbalanced force in this picture?
What happened to the driver in this picture?
Is there evidence of inertia?
Inertia and Mass
Objects will smaller mass have less
inertia (or the tendency to resist
change) than objects with more mass.
Inertia makes it harder to push a bus than a
bike and easier to stop a bike than a bus
moving at the same speed.
More Examples of Newton’s
First Law…
Definition
Four-Square
Picture
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.
Example
Inertia
Other Information
Inertia is the tendency of
objects to resist a change in
motion.
The acceleration of an
object depends on the
mass of the object and
the amount of force
applied.
Let’s break it down
Acceleration of an object
depends on the mass of
the object.
If the force
applied is the
same, the
acceleration of
the empty cart
is greater than
the acceleration
of the full
cart.
Let’s break it down
Acceleration of an object
depends on the amount of
force applied.
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.
Let's study the animations to
understand this a little better.
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.
Remember
Answer: 50 Newtons
Let’s try another one…
____ N ?
1,000 Kg
.1 m/s/s
Our formula would be:
Answer: 100 Newtons
Quiz Time
If the same amount of
force is applied, which
vehicle will accelerate
faster? Why?
Suzie
If Suzie uses 50 Newtons
of force to begin biking
and Billy uses 35 Newtons
of force to begin biking
who will accelerate faster?
Billy
Definition
Four-Square
The acceleration of an
object depends on the
mass of the object and
the amount of force
applied.
Example
Picture
Second
Law
Other Information
The Second Law can be
expressed as a
mathematical equation:
Force = mass x
acceleration
or F = M x A
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!
The shuttle’s
thrusters push the
exhaust gases
downward as the
gases push the
shuttle upward
with an equal
force.
More examples…
The rabbit’s
legs exert a
force on Earth.
Earth exerts an
equal force on
the rabbit’s
legs, causing
the rabbit to
accelerate
upward.
The bat exerts a force on the
ball, sending the ball into the
outfield. The ball exerts an equal
force on the bat, but the bat
does not fly toward the catcher
because the batter is exerting
another force on the bat.
Definition
Four-Square
Picture
For every action
there is an equal and
opposite re-action.
Example
The rabbit’s legs
exert a force on
Earth. Earth exerts
an equal force on the
rabbit’s legs, causing
the rabbit to
accelerate upward.
Third
Law
Other Information
Whenever an object
pushes another object
it gets pushed back in
the opposite direction
equally hard.
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
Works Cited
Much of the information,
graphics, and animation
were gathered from the
following website:
http://teachertech.rice.ed
u/Participants/louviere/Ne
wton/