Download Forces in Motion

Forces in Motion
What Do You Think?
Explain what you know
about Newton’s Laws of
Motion.
Forces in Motion
Newton’s Laws of Motion
In 1686, Sir Isaac
Newton explained the
relationship between
force and motion
with his three laws of
motion.
http://academic.brooklyn.cuny.edu/history/virtual/portrait.htm
Forces in Motion
Newton’s First Law of Motion
1. An object at rest remains at rest until its
acted on by an unbalanced force.
2. An object stays in motion at the same
speed and in the same direction until its
acted on by an unbalanced force.
Forces in Motion
How does this illustrate
Newton’s First Law?
http://www.physicsclassroom.com/mmedia/newtlaws/efarm.htl
Forces in Motion
Newton’s First Law is also called
the Law of Inertia.
Inertia is the tendency of all
objects to resist any change
in motion.
Forces in Motion
Newton’s First Law is also called
the Law of Inertia.
Example…your mom makes a
sharp left turn in the car…you
slide toward the door.
Forces in Motion
Newton’s Second Law of Motion
When applying the same force
on an object, as an
acceleration increases, its
mass decreases.
Forces in Motion
Newton’s Second Law of Motion
If you are applying the same
force on an object, an objects
acceleration decreases as its
mass increases.
Forces in Motion
Newton’s Second Law continued…
• An object’s acceleration
increases as the force on the
object increases
• An object’s acceleration
decreases as the force on an
object decreases.
Forces in Motion
Activity
Tell your neighbor 2
ways a grocery store
shopping cart could
illustrate Newton’s
Second Law?
Forces in Motion
Newton’s Third Law of Motion
• All forces act in pairs.
• If a force is exerted, another
force is exerted that is equal in
size, but opposite in direction to
the first force.
Forces in Motion
Click below to see examples of
Newton’s Third Law
http://www5.unitedstreaming.com/index.cfm
Forces in Motion
Newton’s Third Law also deals with
momentum
• Momentum is a property of a moving
object.
• Momentum depends on the objects
mass and velocity.
• If a small car and a large truck are both
traveling down the highway at the same
velocity, the truck has more mass,
therefore it will have more momentum.
Forces in Motion
Momentum is Conserved
When a moving object hits
another object, the
momentum of the first
object transfers to the
second object.
Forces in Motion
Momentum is Conserved
• Example:
–When one pool ball hits another
pool ball on a pool table, the
momentum of the first ball is
transferred to the second ball as
it hits.
Forces in Motion
The momentum of this truck is
transferred to this car.
http://www.physicsclassroom.com/mmedia/momentum/trece.html