Transcript Section 2B

2-B
Section 2B
Standardized Units
Pages 100-112
2-B
Standardized Unit Systems
 Metric

Système International
 U.S.

system (SI)
customary system (USCS)
Roots from ancient Middle Eastern
civilizations
 Unit
Conversions within systems
 Unit Conversions between systems
U.S. Customary system – Lengths
page 101
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U.S. Customary system – Weights
page 102
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U.S. Customary system – Volumes
page 102
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Example:
 In
the Kentucky Derby, horses race 10
furlongs. How many miles is this?
mile
10 furlongs 
1 furlong
1
8
 1.25 miles
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Conversions within USCS
In 20,000 Leagues Under the Sea, does
the title refer to an ocean depth?
[convert marine leagues to miles]
3 naut.miles
20,000 leagues 
 60,000 naut. miles
1 league
6076.1 ft. 1mile
60,000 naut. miles 

1naut.mile 5280 ft.
 69046.6 miles
Conversions within USCS
If 150 bushels of wheat are traded on
one day, how many cubic inches are
traded?
4 pecks 8 dry quarts
67.2 in3
150 bushels 


1bushel
1 peck
1dry quart
 322,560 in
3
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International Metric System
 Invented


in France, late 18th century
Replace many customary units with
a few basic units
Simplify conversions by using a
base 10 system
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International Metric System
 The




basic units are:
meter (m) for length
kilogram (kg) for mass
second (s) for time
liter (L) for volume
Metric system - Prefixes
Moving between metric units requires shifting the decimal place
one to the right when going to the next smaller unit and one to the
left when going to the next larger unit.
(Example: 5.23 cm = 52.3 mm)
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Examples
 Convert
19 decimeters to millimeters:

Move the decimal 2 places to the RIGHT:

1900 millimeters
 Convert
1378 g to kg:

Move the decimal 3 places to the LEFT:

1.378 kg
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USCS - Metric Conversions
USCS to Metric
Metric to USCS
1 in. = 2.540 cm
1 ft = 0.3048 m
1 yd = 0.9144 m
1 cm = 0.3937 in.
1 m = 3.28 ft
1 m = 1.094 yd
1
1
1
1
1
1
1
1
mi = 1.6093 km
lb = 0.4536 kg
fl oz = 29.574 mL
qt = 0.9464 L
1 gal = 3.785 L
km = 0.6214 mi
kg = 2.205 lb
mL = 0.03381 fl oz
L = 1.057 qt
1 L = 0.2642 gal
Conversions between Metric and
USCS
Convert 20 gallons to liters.
3.785Liters
20 gal 
1gal
 75.7 Liters
Conversions between Metric and
USCS
Convert 105 centimeters to yards.
.
1in
1 ft 1yd
105cm 


2.54 cm 12 in 3 ft
 1.148yd
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Temperature Units
 Fahrenheit

Water freezes at 32ºF, boils at 212ºF
 Celsius

Water freezes at 0ºC, boils at 100ºC
 Kelvin
Water freezes at 273.15K, boils at 373.15K
 Coldest known temperature = 0 Kelvin
(-459.67ºF = -273.15ºC)

Converting Temperatures
page 107
To Convert from
Conversion Formula
Celsius to Fahrenheit
F = 1.8C + 32
Fahrenheit to Celsius
C = (F-32)/1.8
Celsius to Kelvin
K = C + 273.15
Kelvin to Celsius
C = K - 273.15
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You try
A
‘normal’ human temperature is
98.6ºF What is that in Celsius, and
Kelvin?
F  32
C
1.8
98.6-32 66.6

 37 C
1.8
1.8
K  C  273.15
K  37  273.15  310.15K
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Question?
A local weather report says that tomorrow’s
high temperature will be 52º, but does not
specify whether the units are Fahrenheit or
Celsius.
 Can you tell which it is? How?

F  1.8C  32
1.8(52)  32  125.6
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Energy and Power
Energy is what makes matter move or heat up.
The international metric unit of energy is the
joule.
 Power is the rate at which energy is used.
The international metric unit of power is the
watt, defined as

joule
1 watt  1
second
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Energy & Power
A
kilowatt-hour is a unit of energy:
 1 kilowatt-hour = 3.6 million joules
1KW  1hr  
1000 joules
sec
60 min
 60sec

1min
1hr   1hr
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 According
to my electric bill my total
electrical energy usage during the past
12 months was 19,227 KWH.
 And, I was charged (roughly)
$.032/KWH.
 How much did I spent on power in the
last year?
$.032
19227 KHW 
 $615.26
1KWH
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Units of Density/Concentration
 Density
– describes compactness or
crowding.

g/cm3,
people/mi2
 Concentration
describes the amount of
one substance mixed with another.

ppm,
g/100mL (BAC)
• For most states – legal limit is 0.08g/100mL
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Example

Manhattan Island has a population of ≈ 1.5
million people living in an area of about 57
km2. What is its population density? How
much space is available per person?
people
density 
area
1,500,000people

57 km2
 26,000
people
km2
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Example

How much space is that per person?
1km2
26,000people
1km2
1000m 1000m



26,000people 1 km
1 km
 38m2 / person

Which is roughly 6m×6m, or 20ft × 20 ft.
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Example

An average-sized man has about 5L of blood,
and an average 12-ounce beer contains 15g of
alcohol. If all the alcohol were immediately
absorbed into the bloodstream, what would
his BAC be?
15 g alcohol
15 g alcohol
concentration 

5L
5000mL blood
g
 .003
mL
 .003 
100mL
100mL
 0.3
g
100mL
More Practice
A boat is moving at 30 knots (nautical miles per
hour). How fast is this in miles per hour?
30 knots 6076.1 ft 1mile


hr
1knot
5280
 34.52mph
More Practice
Eight ounces of hard liquor typically contain about
70g of alcohol. Consider a 200lb man, with approx.
6 liters of blood, who quickly drinks 8 oz. of hard
liquor. If all the alcohol were immediately
absorbed into his bloodstream, what would his BAC
be?
70 g
70 g
g

 .0116 mL
6 L 6000mL
.0116
g
mL
100mL
g

 1.16
100mL
100mL
More Practice
Now assume his body eliminates the alcohol through
metabolism at the rate of 15g/hr. What is his
BAC 4 hours after drinking the liquor? Is it safe
for him to drive at this time?
15 g
Eliminates 4hr 
 60 g
hr
70 g  60 g  10 g
10 g
g 100mL
g
 .0016

 0.16
6000mL
mL 100mL
100mL
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Homework for Wednesday
Pages 113-117
# 14, 40, 58, 60a,b,c, 71, 73, 94