Download Bell Work 2/23/10

Bell Work: 3/19/14
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. A house of cards is too fragile and must fall
down eventually.
B. If Hannah adds another card to the house
of cards, then it will fall down.
C. If no unbalanced force acts upon the house
of cards, then it will remain standing
forever.
D. 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).
69. Newton’s Laws of Motion
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 1st Law of Motion
Newton’s Second Law of Motion
The acceleration of an object depends on the mass
of the object and the amount of force applied.
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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.
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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 2nd Law of Motion
Newton’s Third Law of Motion
For every action there is an equal and
opposite reaction.
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Newton’s third law can be simply stated as
follows: All forces act in pairs.
Newton’s 3rd Law of Motion
Newton’s Laws Comic Strips
Explain what is going on in the Newton’s
Laws comic strips at the bottom of the
page.
 Give each explanation a title (one of
Newton’s Laws)
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