Unit Conversions Factor Label Method

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Unit ConversionsFactor Label Method
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Dimensional AnalysisFactor Label Method

• Measurements that are made of some aspect of the
  universe must have a quantity and a unit
• Many times, values are not measured in the unit
  that we want
• We have to do some math to get the numbers in the
  form that we desire

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Dimensional AnalysisFactor Label Method

• To convert a measurement from one unit to
  another, multiply the known quantity and unit(s)
  by a conversion factor

Quantity with x Conversion Quantity with
Wrong Unit x Factor Desired Unit
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Conversion Factors

• The chosen conversion factor cancels all units
  except those desired for the answer
• Conversion Factors come from equalities
• Equalities yield two conversion factors
• 1 ft 12 in

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Conversion FactorsChoosing the Correct
Conversion Factor

• Example Convert 179,800 s to minutes

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Conversion FactorsChoosing the Correct
Conversion Factor

• Write Measurement with wrong units
• Write Multiplication Sign, Fraction Bar
• Write the unit that you want to cancel on the
  bottom of the fraction. Write the desired unit
  on the top of the fraction
• Fill in the fraction with the numbers that make
  the numerator denominator of the fraction
  equivalent
• Cancel Units ? PLUG CHUG!!! ? Round to the
  proper number of SF

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Conversion FactorsMultiple Steps

• Each conversion factor should cancel out a unit
  from the previous measurement (or conversion
  factor)
• Convert 179800 s to days

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Conversion FactorsMultiple Steps with Complex
Units

• Each conversion factor should cancel out a unit
  from the previous measurement (or conversion
  factor)
• Convert 65.0 mi/hr to m/s
• 1 mi 1.6 km