Chapter 1, Section 1 Measuring Motion

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Chapter 1, Section 1 Measuring Motion
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• When an object changes position over time, the
  object is in motion.
• .

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• Motion can be observed by using a reference
  point. A reference point is an object that
  appears to stay in place compared to a moving
  object. This allows you to tell that the object
  is in motion
• Reference point Example trees, buildings,
  Earths surface

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• Speed is the amount of time it takes you to
  travel a specific distance.
• To calculate speed
• Average speed total distance
• total time
• The units for speed are m/s, km/h

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Objects with speed
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• Velocity is the speed of an object in a
  particular direction.Velocity must include a
  direction.
• (north, south, left, right)
• To calculate velocity total distance
  direction
• total time

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• Velocity is only constant if speed and direction
  do not change. Constant velocity is the motion of
  a
• straight line.
• If there is a change in speed ( 15 m/s to 20 m/s)
  or direction (east to west), the velocity will
  change.

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Rocket changing velocity
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• To combine velocities, it depends on whether the
  object is traveling in the same direction or
  different direction. The result is the resultant
  velocity.
• Same direction add velocities together
• 10 m/s north 5 m/s north 15 m/s north
• Different direction Subtract velocities
• 15 m/s west 10 m/s east 5 m/s west

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• Acceleration is the rate at which velocity
  changes. If an objects speed or direction
  change, its velocity changes.
• An increase in velocity positive acceleration
• A decrease in velocity negative acceleration or
  deceleration

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Roller coaster have positive and negative
acceleration!
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• To calculate acceleration
• Average acceleration final velocity-starting
  velocity
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  time it takes to change velocity
• a Vf- Vi
• t
• Units for acceleration m/s2

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• When observing a graph you can determine if
  acceleration is positive or negative based upon
  the slope. It the slope goes upward it is
  positive acceleration. If the slope goes
  downward, it is negative acceleration.

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• Centripetal acceleration occurs when an objects
  travels in circular motion.
• Example the Earth rotating!