Dimensional
Analysis
Monday, August 17th, 2015
What’s the Rule?
What’s the Rule?
What’s the Rule?
Unit Conversion Factor
A fraction whose numerator
and denominator are
equivalent
(you can also use the reciprocal)
To solve a dimensional analysis
problem you want to choose a unit
conversion factor that…
• Introduces the unit you want in the
answer
• Cancels out the original unit so that the
one you want is all that is left.
“Canceling out” Words
inches
inches feet


feet miles
miles
seconds hours

minutes seconds
hours

minutes
Practice: Choose the appropriate
conversion factor.
Inches to
feet
inches
1
Minutes to
hours
Meters to
centimeters
minutes
1
meters
1
1 ft
12 in.
12 in.
1 ft
60 min
1 hr
1 hr
60 min
1m
100 cm
100 cm
1m
Abbrev
Factor = 1
base unit
Megakilohecto-
M
k
h
10-6
10-3
10-2
decicentimillimicronanopico-
d
c
m
µ
n
p
101
102
103
106
109
1012
Metric Conversions
Prefix
Examples
One bag of apples weighs 64 ounces.
How many pounds does it weigh?
1 lb
64  1 lb
64 oz 

= 4 lb
16 oz
16
Darren drank 2 liters of water. How many
milliliters of water did he drink?
1000 mL
2  1000 mL
2L 

= 2000 mL
1L
1L
Convert 80 miles per hour to feet per hour.
80 mi 5,280 ft 80  5280 ft 422,400 ft



1 mi
1 hr
1 hr
1 hr
Convert 63,360 feet per hour to miles per hour.
63,360 ft
63,360 ft  1 mi 12 mi
1 mi



1 hr
1 hr  5280 ft
1 hr
5280 ft
D.A. Activity #1
Practice in your notebook
1. Convert 38 cm to m
2. Convert 417 mg to g
3. Convert 80 m to km
4. Convert 0.0025L to nL
5. Convert 0.17 m to mm
1. Convert 38 cm to m
2. Convert 417 mg to g
D.A. Activity #1 Answers
1. 0.38 m
2. 0.417 g
3. 0.030 km
4. 2,500,000 nL
5. 170 mm
D.A. Homework WKST #1
Complete the half sheet of practice
problems in your notebook
Answers to the Intro to DA half sheet
1. 3.2 feet
2. 11.5 inches
3. 75 feet
4. 5.7 meters (this is a rough guess)
5. 2.9 feet
6. 1.4 meters
7. 0.87 meters
8. 420 centimeters