Transcript Lesson PPTx - Lindbergh Schools

Newton’s Laws
WHY
SHOULD
I
WEAR
MY
SEATBELT?
What do you think about seatbelts?
Use your clicker to take the
Seatbelt Survey.
Answer honestly, we just want
to know current views about
seatbelts.
Seatbelts and Newton’s Laws
Understanding Newton’s
Laws helps us understand the
importance of seatbelts.
Let’s get started…
Newton’s 1st Law of Motion
What does it say?
An object in motion tends to stay
in motion with a constant velocity
and an object at rest tends to stay
at rest unless acted upon by a net
force.
So what does that mean?...
Newton’s 1st Law of Motion
 It means…
An object will tend to keep doing what
it’s doing unless a force makes it do
something else (speed up or slow
down).
This is called inertia – the tendency of
an object to maintain its current state
of motion.
How does this show Newton’s 1st Law?
Newton’s 1st Law of Motion
This law is also known as
The Law of Inertia.
Watch the demos!
http://teachertech.rice.edu/Participants/louviere/Newton/law1.html
One last thing about the 1st Law…
Don’t try this one on the test…
http://foxinthehenhouse.files.wordpress.com/2011/03/calvin-on-scientific-law.gif
Newton’s 2nd Law of Motion
 What does it say?
The
acceleration of an object is
directly proportional to the net
external force acting on the object and
inversely proportional to the mass of
the object.
 So what does that mean?
Newton’s 2nd Law of Motion
That means…
If
force is increased, acceleration
will increase
(directly proportional)
If mass is increased, acceleration
will decrease
(inversely proportional)
Newton’s 2nd Law of Motion
 So how could I relate Force, Mass,
and Acceleration at the same time?
In
a mathematical equation of course!
F=m*a
Force
in Newtons (N)
Mass
in Kilograms (kg)
Acceleration
in meters / sec
(m/s)
Newton’s 2nd Law of Motion
If the same force is applied to both the ball and the wall,
which will have the greater acceleration?? Why?
http://teachertech.rice.edu/Participants/louviere/Newton/law2.html
Newton’s 3rd Law of Motion
What does it say?
For
every action there’s an
equal but opposite reaction
So what does that mean?
Newton’s 3rd Law of Motion
It means…
Forces
exist in pairs called
‘action-reaction’ pairs.
When a bat applies a force to a
ball, the ball applies an equal
but opposite force on the bat.
Newton’s Law and a Car Crash
 When in a car crash, there are 3
collisions:
1.
2.
3.
Your car with the other object.
Your body with the car.
Your organs with the inside of your body.
 Can you relate this to all 3 laws?
The Importance of Seat Belts
 Do the following as you read the article:
 Find 3 places where the 1st law is
illustrated. Highlight them and label them
1A, 1B, and 1C.
 Find 3 places where the 2nd law is
illustrated. Highlight them and label them
2A, 2B, and 2C.
 Find 3 places where the 3rd law is
illustrated. Highlight them and label them
3A, 3B, and 3C.
The Importance of Seat Belts
 After you read the article:
Make an advertisement or bumper sticker that advocates
wearing your seat belt. These will be hung in the hall…so
make sure all content is appropriate.
 On a separate sheet of paper, answer the following:
1. Relate your ad/bumper sticker to all 3 of Newton’s
Laws.
2. Explain if your view of wearing seatbelts has changed.
Explain.
3. Use Newton’s Laws to describe how YOU not wearing
your seat belt or having unrestrained items in your
car could harm your passengers.
