MOTION

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MOTION

• speed, velocity and acceleration

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• Motion Notes
• What is motion?
• Motion is relative
• Displacement vs. Distance
• Constant vs. Changing Motion
• Three possible motions

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What is Motion?

• Motion occurs when an object changes position
• The position of the object depends on your frame
  of reference.
• A frame of reference refers to the stationary
  background to which the objects position is
  compared.

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Motion is relative

• Motion is relative to a chosen frame of
  reference.
• You at rest at your tableare you moving?
• Relative to the floor?
• Relative to the school building?
• Relative to the ground?
• Relative to the Sun?
• Relative to the Galaxy?
• Relative to the Universe?
• http//www.phy.ntnu.edu.tw/java/relativeVelocity/r
  elativeVelocity.html
• http//www.classzone.com/books/ml_science_share/vi
  s_sim/mfm05_pg7_relmotion/mfm05_pg7_relmotion.html
  

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Descriptions of Motion

• Relative motionmotion of objects as perceived
  from your frame of reference
• Linear motionmotion of objects moving in
  straight lines (opposite of non-linear)
• Constant motionmotion of objects in mechanical
  equilibrium (no change in motion)
• Changing motionmotion of objects that are
  accelerating

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Displacement vs. Distance

• Displacement is the distance and direction of an
  objects final position from its initial
  position.
• Distance is the length of the path that the
  object travels.

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Three Possible States of Motion

• At rest
• Constant velocity (same speed and direction)
• Acceleration (changing speed and/or direction)

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Describing Motion

• By definition
• By comparison
• By measurements
• By equations
• By graphs

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SPEED IS

• HOW FAST AN OBJECT MOVES.
• total distance covered divided by time it takes
  to cover that distance
• Speed equation v d/t
• SI unit is meters/second (or m/s)
• Example 40 m/s

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VELOCITY IS

• SPEED IN A GIVEN DIRECTION
• Speed is determined by the speed equation
• Direction of speed is described
• SI unit is m/s and direction
• example 40 m/s east

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ACCELERATION

• The rate of change in velocity over a period of
  time.
• SI unit is m/s2
• example 4.5 m/s2 or - 4.5 m/s2
• Positive means speeding up, negative means
  slowing down
• Velocity changes in two ways
• 1 a change in speed (acceleration or
  deceleration)
• 2 a change in direction (turning)

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ACCELERATION EQUATION

• Acceleration final velocity initial velocity
• final time
  intial time
• a vf - vi
• tf - ti

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GRAPHING SPEED

• Two types of graphs
• Distance-time graphs
• Velocity-time graphs

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RELATIVE MOTION WEB SITES

• http//www.phy.ntnu.edu.tw/java/relativeVelocity/r
  elativeVelocity.html
• http//www.physicsclassroom.com/mmedia/kinema/kine
  maTOC.html
• http//hyperphysics.phy-astr.gsu.edu/hbase/relmot.
  html
• http//www.ii.metu.edu.tr/emkodtu/met106/lectures/
  motion_in_2_and_3d/page9.html

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RELATIVE MOTION

• Motion relative to your perspective or frame of
  reference.
•  In order to see an object in motion, you need a
  perspective or frame of reference, such as a
  stationary background, for comparison.

RELATIVE MOTION