Download Formula for Newton`s Second Law of Motion

Activity #42 Newton’s Second
Law of Motion
Newton’s Second Law of Motion
nd
2
Newton’s
Law of Motion
States…
• An unbalanced force acting on
an object causes the object to
accelerate in the direction of the
force.
Wagon moves
this way
Unbalanced
Force Applied
• You might unconsciously know the Second
Law. Heavier objects require more force to
move the same distance as lighter objects.
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4
Force, Acceleration, and Mass
• The greater the force applied
to a given object, the greater
its acceleration.
Newton’s Second Law in Real
Life
• Using Newton’s second law
of motion, explain why
larger trucks usually need
more distance to stop than do
smaller trucks.
Formula for Newton’s Second
Law of Motion
• FORCE = MASS x ACCELERTATION
• F =force, m= mass, and a
=acceleration.
What does F = ma say?
F = ma basically means that the force of an
object comes from its mass and its
acceleration.
Something very massive (high mass)
that’s changing speed very slowly (low
acceleration), like a glacier, can still
have great force.
Something very small (low mass) that’s
changing speed very quickly (high
acceleration), like a bullet, can still
have a great force. Something very
small changing speed very slowly will
have a very weak force.
NewtoN’s secoNd Law con’t.
F= M x A
Force = Mass x Acceleration
the units:
• force is measured in Newtons (N)
• 1 N= 1kg x 1 m/s2
• mass is measured in kilograms (kg)
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9
• 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 0.5 m/s2. Using
Newton's Second Law, you
can calculate how much force
Mike is applying to the car.
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10
• F=MxA
• F= 1000 kg x .5 m/s2
• F= 500 k x m/s2
•F= 500 N
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Reserved.
11
Examples
• What force is needed to push a
2
10kg shopping cart at 3 m/s ?
• F=m x a
• F= 10 kg x 3 m/s2
• F= 30 N
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Reserved.
12
Question
• Identical twins are riding in
identical wagons. A friend gives
the first wagon a stronger push
than the second. Which twin will
experience greater acceleration?
Question
• Would a car towing a boat take
less, the same, or more time to
accelerate than it would without
the boat? Explain.
Question
• What will happen to the
acceleration of an object if the
mass decreases and the force is
constant?
Question
• If two identical objects
accelerate at the same rate, what
must be true of the force
applied to each object?