What time is it

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What time is it?

• Velocity Time!

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Math

• m?
• m3
• b?
• b0
• y mx b
• y 3x 0 3x

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Physics

• m 3
• v 3 m/s
• b 0
• yi 0 m
• y mx b
• y 3t 0 3t

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Math

• m ?
• m -2
• b ?
• b 10
• y mx b
• y -2x 10

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Physics

• m -2
• v -2 m/s
• b 10
• xi 10 m
• y mx b
• x -2t 10

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MIB
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m and b

• In both of our examples,
• The slope, m, was equal to the velocity
• Already knew that
• The y intercept, b, was equal to the initial
  position of the object
• Does this make logical sense?
• b initial position

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Equations of motion

• In the case of a constant velocity, we will be
  graphing a straight line.
• In slope-intercept form, that will be
• x vt xi
• Or in vector notation
• d vt di

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Useful?

• A friend owes you money. He sees you 3 m away and
  begins walking briskly at a velocity of 2 m/s.
  Where is he after 7.5 s?
• Would you rather

• Make a table
• Plot the points
• Make a graph
• Interpolate
• OR
• Plug 3 numbers into an equation

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A10 m
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A?
A?
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• What does the position vs. time graph look like?

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• rate of change Slope
• rate of change of position Velocity
• rate of change of velocity Acceleration
• rate of change of acceleration Jerk
• Just as position and velocity are vectors,
  acceleration is a vector

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• Area under the curve of velocity ?x
• Area under the curve of acceleration ?v
• (Area under the curve of jerk ?a)