Unit Conversions

1
MEASUREMENT

• Unit Conversions

2
Number vs. Quantity

• Quantity - number unit

UNITS MATTER!!
3
The Metric System

• Easier to use because it is based on powers of
  10.
• A metric unit has two parts
• A prefix and a base unit
• Example cm, mL, mg
• The prefix tells you how many times to divide or
  multiply by 10

4
Some Base Units

• Length - meter(m) - more than a yard
• Mass - grams(g) - about a raisin
• Volume - Liter(L) - half of a two liter bottle

5
Some Prefixes

• Mega M 1000000 times
• kilo k 1000 times
• Hecto h 100 times
• Deka dk 10 times
• BASE
• deci d 1/10
• centi c 1/100
• milli m 1/1000
• Micro µ 1/1000000
• Nano n 1/1000000000
• Pico p 1/1000000000000

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Intro to Dimensional Analysis

• How long can you hold your breath?
• Convert it to DAYS!

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Dimensional Analysis

• The Factor-Label Method
• Units, or labels are canceled, or factored out

8
Dimensional Analysis

• Steps
• 1. Identify starting ending units.
• 2. Line up conversion factors so units cancel.
• 3. Multiply all top numbers divide by each
  bottom number.
• 4. Check units answer.

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Conversion Factors

• Conversion factor- a fraction based on a
  definition and equal to 1
• Example
• 1 cm 0.01 m
• Conversion factors possible 1 cm 0.01 m0.01
  m OR 1 cm

10
Dimensional Analysis

• Your European hairdresser wants to cut your hair
  8.0 cm shorter. How many inches will he be
  cutting off?

8.0 cm
1 in 2.54 cm
3.2 in
11
F a c t o r - L a b e l
C o n v e r t 1 0 0 0 g r a m s t o p o u
n d s When 1 pound is equal to 454 g. g ? lbs
1 p o u n d
1 0 0 0 g

2 . 2 p o u n d s
4 5 4 g
12
Dimensional Analysis

• Taft football needs 550 cm for a 1st down. How
  many feet is this?

550 cm
1 in 2.54 cm
1 ft 12 in
18 ft
13
Dimensional Analysis

• If there are 5280 ft in 1 mile, and you run 8.5
  miles, how many cm did you run?
• 1 in 2.54 cm

14
Questions?

• The ultimate measure of a person is not where
  they stand in moments of comfort and convenience,
  but where the stand in times of challenge and
  controversy.