Stuff on Arithmetic and Units

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Stuff on Arithmetic and Units
Can we do this 1 .00 ft 3 in
???? How about this 1.00 ft 0.25 ft
1.25 ft Can we do this 1.00 ft x 3 in
3 ft-in And this 1.00 ft x 0.25 ft 0.25
ft2 And this 1.00 ft ? 0.25 ft 4.00
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More on Arithmetic and Units

• Have you noticed yet that units can be multiplied
  and divided just like numbers or variables? They
  act like numbers or variables and are manipulated
  separately from them.
• EXAMPLE

Units.
Where did the atm unit go? It canceled because
atm/atm 1
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Dimensional AnalysisMethod for converting from
one unit to another
FACT Any expression can be multiplied by 1
without changing its value. SoWhat is 1 anyway ?

Consider 1 ft 12 in
Isnt this fraction equal to 1, too? This is an
example of a conversion factor
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Conversion Factors
Suppose we flip it or invert it?
The inverted fraction is still equal to 1. Ok,
now we have TWO conversion factors for changing
from feet to inches or inches to feet.
AND
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More on Conversion Factors
The VALUE of that distance is the same whether I
say it is 1 foot or 12 inches. (A carpenter can
use 1 ft or a 12 inch board for the same job.)
How many inches in 42.7 feet? Multiply 42.7 feet
by the correct conversion factor
Now, 42.7 ft has the same value as 512 in. The
units are just different.
(42.7 ft)
512 in