Transcript Bell Work 2/23/10 - Rutherford County Schools

Bell Work: 3/26/12

Write about something scientific you did
over spring break.
TCAP Practice Book
Complete Part I of the science section
pgs. #1-35.
 Answer each question. You will have 30
minutes.
 Discuss answers and justify your answers.
Explain next to the question the answer
choice is correct.

Bell Work: 3/27/12
Hannah just finished building a house of cards
that stands four-stories high. She is worried that
it will fall down.
Which of the following statements is definitely
true?
A.
B.
C.
D.
A house of cards is too fragile and must fall
down eventually.
If Hannah adds another card to the house of
cards, then it will fall down.
If no unbalanced force acts upon the house
of cards, then it will remain standing forever.
As long as nobody touches the house of
cards, it will remain standing.
Objectives
 Identify
and explain how Newton’s
laws of motion relate to the
movement of objects (SPI 0707.11.4).
Newton’s First Law of Motion
An object at rest remains at rest, and an object in
motion remains in motion at a constant speed and in a
straight line unless acted on by an unbalanced force.
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Net force = combination of all of the forces acting
on an object
When net force is 0 N, the forces are balanced.
When the net force on an object is not 0 N, the
forces on the object are unbalanced.
Newton’s first law of motion is sometimes called the
law of inertia.
Inertia is “want to,” when an object resists change
because it “wants to” keep going in a straight line.
Inertia depends on an object’s mass.
The more mass an object has, the more inertia an
object has.
Newton’s Second Law of Motion
The acceleration of an object depends on the mass
of the object and the amount of force applied.
•
Weight vs. Mass
• Weight is a measure of gravity on an object.
• Mass is the amount of matter (what an object is
made of) in an object.
•
F (force) = m (mass) x a (acceleration)
• F=mxa
a (acceleration) = F (force) ÷ m (mass)
• a=F÷m
•
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If you want to increase the acceleration of an
object, you need to decrease its mass.
Newton’s Third Law of Motion
For every action there is an equal and
opposite reaction.
•
Newton’s third law can be simply stated as
follows: All forces act in pairs.
Bell Work 3/27/12
1.
2.
What is friction?
Question…

Why do you think the sponge shown below has
a layer of plastic bristles attached to it?
Relate the Diet Coke
and Mentos
demonstration to
Newton’s 3rd Law.
Momentum
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Imagine a compact car and a large truck
traveling with the same velocity. The drivers
of both vehicles put on the brakes at the
same time. Which vehicle will stop first?
The car because a larger force is needed to
stop the truck. The truck has more
momentum because it has more mass.
The momentum of an object depends on
the object’s mass and velocity. The more
mass an object has, the more
momentum it has.
Work Order:
1.
2.
3.
4.
Word Problem & Newton’s Laws
Sheet
Extra Credit
Study Island: Force & Motion
Study Guide