Chapter 10 Notes Ch 10pg1

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Chapter 10
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Section 1 - The Nature of Force

• Force - a push or pull
• Unbalanced Forces - acting on an object will
  change the objects motion
• Balanced Forces - acting on an object will not
  change the objects motion
• Inertia - the tendency of an object to resist a
  change in its motion

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Newtons First Law of Motion

• An object at rest will remain at rest, and an
  object that is moving at a constant velocity will
  continue moving at constant velocity unless acted
  upon by an unbalanced force.

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Section 2 - Force, Mass and Acceleration

• Newtons Second Law of Motion
• Force Mass x Acceleration Fma
• Force Newtons (N),Masskilograms (kg),
  Acceleration m/sec2
• Mass - the amount of matter in an object (SI
  units kilogram (kg))
• Sample Problems pg.321

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Section 3 - Friction and Gravity

• Friction - The force that one surface exerts on
  another when the two rub against each other.
• The strength of the force of friction depends on
  two factors the types of surfaces involved and
  how hard the surfaces push together

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Friction (cont.)

• Is friction bad? ice, walking, car, bike
• Types of friction
• sliding friction - objects slide against each
  other
• rolling friction - object is round or has wheels
• fluid friction - object moves through fluid
  (swimming)

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Gravity

• The force that pulls objects toward Earth (g
  -9.8m/sec2)
• Free fall - only gravity acting on the object (in
  a vacuum)
• Projectile motion - throw object horizontally
  (football, soccer)
• Air resistance - fluid friction
• Terminal velocity - greatest velocity an object
  in free fall can have
• air resistance forces balanced with gravity

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Gravity (cont.)

• Weight - measure of the force of gravity on an
  object
• Mass - measure of the amount of matter in an
  object
• Weight mass x acceleration due to gravity
  Wmg
• Law of Universal Gravitation - The force of
  gravity acts between all objects in the universe.

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Section 4 - Action and Reaction

• Newtons Third Law of Motion
• If one object exerts a force on another object,
  then the second object exerts a force of equal
  strength in the opposite direction of the first
  object.
• Action-Reaction - Squid pg.333, skater, kick,
  walking
• Forces cancel? Volleyball pg.334

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Momentum

• Momentum mass x velocity
• Sample problems pg.335
• Law of Conservation of Momentum
• The total momentum of any group of objects
  remains the same unless outside forces act on the
  objects.
• Train examples - overheads pg.337

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Section 5 - Orbiting Satellites

• Rocket lift off - Newtons third law - gasses
  expelled with a downward force, exert an equal
  but opposite force upward on the rocket.
• Satellite - any object that travels around
  another object in space
• centripetal force - any force that causes an
  object to move in a circle

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Orbiting Satellites (cont.)

• satellites in orbit around the Earth continually
  fall toward Earth, but because Earth is curved
  they travel around it pg.340
• Satellite Motion

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Chapter 10 Vocabulary

• force
• net force
• inertia
• Newtons first law
• Newtons second law
• Newtons third law
• friction

• gravity
• momentum
• conservation of momentum
• satellite
• centripetal force