MOTION

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MOTION

• Chapter 11
• Physical Science Concepts in Action
• Wysession and Borga

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For our discussion

• Lets agree that motion is more of a gross motor
  motion.
• Not blood flowing through veins, eyes blinking,
  feet tapping

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Are you moving?

• Are you moving
• Are you moving?
• Are you moving?
• Are you moving?
• Are you moving?

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• Relative
• to
• what?

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Frame of Reference

• Change in position compared to a fixed point.
• A system of objects that are not moving with
  respect to one another.

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Frame of ReferenceReference point
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Choosing a meaningful frame of reference

• Allows you to describe motion in a clear and
  relevant manner.

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• Motion is a change in position compared to a
  fixed spot.

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Types of Motion

• Translational Motion
• (straight line)
• Vibrational Motion
• (movement from a
  center position, back forth)
  
• Circulation Motion
• (movement around a central
  position)

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Change in position can be

• Distance the length of a path between two
  points.
• Displacement -- is the direction from the
  starting point and the length of a straight line
  to the ending point

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Vector

• Displacement is an example of a vector
• A vector is a quantity that has magnitude and
  direction

resultant
resultant
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• Speed is how quickly an object changes position.
• This is measured in distance/time

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Describing speed

• Average speed is computed for the entire trip.
  
  Total distance/Total
  time
• Instantaneous speed is measured at a particular
  instant.

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Velocity

• Speed and direction are described
• Velocity is a vector
• A change in velocity can result in
• A change of speed
• A change of direction
• Or both a change of speed and direction

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Acceleration

• A change in velocity
• A change in speed
• Or a change in direction
• Or a change in both speed and direction

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Acceleration

• Can be
• Positive (increasing)
• Or negative (decreasing)

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Example of acceleration

• Free fall
• Movement of object toward Earth just because of
  gravity
• Meters/second/second or meters/seconds squared
• Free fall increase in speed is 9.8 m/s/s or 32
  ft/s/s
• Called acceleration due to gravity.

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Another example of acceleration

• A horse on a carousel going around in a circle

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Acceleration

• Acceleration change in velocity
• Total time for change