Transcript Forces - Solon City Schools

Forces
Laws of Motion
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Newton’s First Law of Motion
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An object at rest remains at
rest and an object in motion
maintains its velocity unless
it experiences an
unbalanced force.
Inertia is the tendency of an
object at rest to remain at
rest, if moving, to continue
moving at a constant
velocity.
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People leaning to the curve
as a car drives around a
curve.
Seatbelts fight inertia
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Newton’s Second Law of Motion
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The unbalanced force acting
on an object equals the
object’s mass times its
acceleration.
Force equals mass times
acceleration.
Force = mass x acceleration
F = ma
Force is measured in units
called Newtons.
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Newton’s Second Law of Motion
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The acceleration of an
object is proportional to the
net force on the object and
inversely proportional to the
object’s mass.
acceleration = force / mass
a=F/m
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Which of Newton’s Laws of Motion
states that for is the product of
mass and acceleration
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First Law
Second Law
Third Law
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What units is force measured
in?
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grams
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Which of Newton’s Laws of Motion states
that an object at rest, remains at rest and an
object in motion remains in motion at a
constant velocity unless acted upon by an
outsice force?
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First Law
Second Law
Third Law
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Gravity
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Law of Universal Gravitation
states that all objects in the
universe attract each other
through gravitational force.
F = G (m1 m2/d2)
Gravity depends on:
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Mass of the objects
Distances between objects
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Free Fall
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Free fall is when gravity is
the only force acting on an
object.
Weight = mass x free-fall
acceleration
w = mg
Acceleration due to gravity is
9.8 m/s2
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Terminal Velocity
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Terminal velocity is the air
resistance is equal to the
gravitational force.
When terminal velocity
occurs, maximum velocity is
reached.
A free falling object
accelerates until the object
reaches terminal velocity.
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Projectile Motion
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Projectile motion is the
curved path an object
follows when thrown,
launched, or otherwise
projected near the surface of
the earth.
An object thrown will hit the
ground at the same time that
an object is dropped from
the same height.
Gravitational acceleration is
9.8 m/s2.
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Newton’s Third Law of Motion
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For every action force, there
is an equal and opposite
reaction force.
Forces always occur in
pairs.
Force pairs do not act on the
same object.
Equal forces don’t always
have equal effects.
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Momentum
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Momentum is a property of
all moving objects, which is
equal to the product of the
mass and the velocity of the
object.
Momentum=mass x velocity
p = mv
The Law of Conservation of
Momentum states that the
total amount of momentum
in an isolated system is
conserved.
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Test
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Thursday, October
15th?
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Review Questions:
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Which of Newton’s laws of motion states that force is the
product of mass and acceleration?
Newton’s Second Law of Motion
What is the numeric value of gravitational acceleration?
9.8 m/s2
What is the formula for calculating momentum?
p=mv
Which law states that the total amount of momentum in an
isolated system is conserved?
Law of the Conservation of Momentum
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Review Questions:
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What do we call the resistance to change in motion?
Inertia
Which will hit the ground first, a crumpled sheet of paper or an
uncrumpled sheet of paper?
crumpled sheet of paper
What is the momentum of a 4000 kg car traveling at 12 meters
per second?
48,000 kg x m/s2
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Review Questions:
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Which of Newton’s laws of motion states that for every force
there is an equal and opposite reaction force?
Newton’s Third Law of Motion
What is the force of attraction between any two objects?
Gravity
Which will reach the ground first, a ball thrown or the same type
of ball dropped from the same height?
Both reach the ground at the same time
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Review Questions:
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What is the formula for calculating force?
F=ma
What is the formula for calculating weight?
w=mg
Why does a skydiver slow down when his parachute is
deployed?
Air resistance
What do we call the curved path an object follows when thrown,
launched, or otherwise projected near the surface of the earth?
Projectile motion
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Review Questions:
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Which of Newton’s law of motion states that an object at rest
will remain at rest and an object in motion at a constant velocity
will remain in motion at a constant velocity unless acted upon
by an unbalanced force?
Newton’s First Law of Motion
What do we call the speed of a free falling object when the air
resistance is equal to the force of gravity?
Terminal velocity
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Review Questions:
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In what metric units do we measure force?
Newtons
What law states that there is an attraction between any two
objects?
Law of Universal Gravitation
What is the acceleration of a 18 kilogram skateboard when you
apply the force of 3.5 newtons?
0.194 m/s2
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