Physics Flipped Notes

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• Physics Flipped Notes
• Take notes on this powerpoint in your journal.
  Title your journal
• Forces and Motion

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Forces and Motion

• Demonstrate and calculate how unbalanced forces
  change the speed or direction of an objects motion

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Force

• Any push or pull on an object
• Acts in pairs
• Measured in Newtons (N)
• Every force has a magnitude and direction
• Forces can work together or against each other
• Forces can be balanced or unbalanced

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Vectors

• Lines with arrows that show direction and
  magnitude of a force.
• Length of the line shows the amount of force
  (magnitude)
• The arrow shows the direction of the force.

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Balanced Forces

• Do not cause a change in motion
• Occurs when objects are at rest or traveling at a
  constant speed and direction.

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Balanced forces
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Unbalanced Forces

• Always cause a change in motion
• Occurs when there is a change in speed or
  direction of motion

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Net Force

• Combination of all forces acting on an object.
• Add forces working in the same direction.
• 2 N
• 8 N Net Force 8 2 10 N
• Subtract forces that are working in opposite
  directions.
• 7 N 3 N Net Force 7 3
  4 N

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Add forces acting in the same direction

• Example
• 8 N 6 N 14 Newtons

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Subtract forces acting in opposite directions

• Example
• 20 N 18 N 2 Newtons

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Net Force 0Forces are balanced

• Example
• 20 N 20 N 0 Newtons
• Forces are balanced - No change in motion

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Newtons 1st Law of Motion

• States that
• An object at rest will stay at rest unless acted
  on by an unbalanced force.
• And
• An object in motion will stay in motion at the
  same speed and direction unless acted on by an
  unbalanced force.

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In other words

• An object will keep doing what it is doing unless
  forces become unbalanced
• Also known as the Law of Inertia
• Inertia An objects tendency to resist change

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Law of Inertia (1st law)
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Newtons 2nd Law of Motion

• The acceleration of an object by a force is
  inversely proportional to the mass of the object
  and directly proportional to the force applied.

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In other words

• The smaller the object, the greater the
  acceleration AND the larger the object, the
  smaller the acceleration.
• The smaller the force applied, the smaller the
  acceleration AND the larger the force applied the
  larger the acceleration.

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Therefore

• Force Mass X Acceleration F ma
• Example Force 1,000 kg X .05 m/s/s
• Force 50 Newtons

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Newtons 3rd Law of Motion

• For every action, there is an equal but opposite
  reaction

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In other words

• All forces act in pairs.
• When one object exerts a force on a second
  object, the second object exerts a force back
  that is equal in size but opposite in direction

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Newtons 3rd Law
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Space Shuttle LaunchExample Action-Reaction
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Speed

• How fast an object is moving
• Rate at which an object covers a distance
• Speed distance time

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Example Calculating Speed

• While on vacation, Lisa Carr traveled a total
  distance of 440 miles. Her trip took her 8
  hours. What was her average speed?
• Speed distance time
• Speed 440 miles 8 hours
• Average speed 55 miles/hour

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Whats the difference between Speed and Velocity?

• Velocity - The rate at which an object changes
  position. Its the measurement of the rate and
  direction of motion.

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Work

• Occurs when a force is used to move an object
  through a distance
• Measured in Joules(J) Newtons/meter
• Work Force (N) X Distance (m) W Fd
• How much work is done if a force of 20N is used
  to displace an object 3m?
• Work (20N) X (3m)
• Work 60 Joules (J)

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THE END