1. Dimensional Analysis
Chapter 2

2. Systems of Units Section 2.3
Physical Quantity
Unit
Abbreviation
Mass
Kilogram
Gram (CGS) kg
Length
Meter
Centimeter (CGS) m
Time
Second s
Temperature
Kelvin K
Amount of substance
Mole
mol
Electric Current
Ampere A
Luminous intensity
Candela cd

3. Derived Units Quantity Unit Symbol Equivalent in Terms of Base Units
Volume
liter L
0.001 m3
1000 cm3
Force
newton (SI)
dyne (CGS) N
1 kg ∙ m/s2
1 g ∙ cm/s2
Pressure
pascal (SI) Pa
1 N/m2
Energy, work
joule (SI)
erg (CGS)
gram-calorie J
cal
1 N ∙ m = 1 kg ∙ m2/s2
1 dyne∙cm = 1 g∙cm2/s2
4.184 J = kg ∙ m2/s2
Power
watt W
1 J/s = 1 kg ∙ m2/s2

4. Section 2.2 Dimensional Analysis
Utilizes conversion factors in order to convert between units of one thing to units of something else
Examples of conversion factors:
1 foot = 12 inches
2.54 cm = 1 inch

5. Example How many centimeters are in 1.39 feet? Hint: 1 in = 2.54 cm
See Sample Exercise 1.9 (Pg. 25)
42.4 cm

6. Conversions Involving More than One Unit
The speed of sound in air at sea level is 340 m/s. Express this speed in miles per hour.
Hint: 1 mile = km
See Sample Exercise 1.10 (Pg. 26) and Useful Conversion Factors and Relationships (Inside back cover)
760 mile/hr

7. Conversions Involving Cubed Units
Express a density of 8.4 g/cm3 in terms of SI base units (kg/m3).
See Sample Exercise 1.11 (pg )
8400 kg/m3 OR 8.4 x 103 kg/m3

8. Combination
Carry out the following conversion: 0.04 g/min ∙ m3 to lbm/hr ∙ ft3
1.5 x 10-4 lbm/hr ∙ ft3

9. For Super Duper Fun
In 1916 Nusselt derived a theoretical relation for predicting the coefficient of heat transfer between a pure saturated vapor and a colder surface: where h = mean heat transfer coefficient, Btu/(hr)(ft2)(ºF) k = thermal conductivity, Btu/(hr)(ft)(ºF)  = density, lb/ft3 g = acceleration of gravity, 4.17 x 108 ft/(hr)2  = enthalpy change, Btu/lb L = length of tube, ft  = viscosity, lbm/(hr)(ft) T= temperature difference, ºF What are the units of the constant, 0.943?

10. Assignments Complete the following questions at the end of Chapter 2:
2.1, 2.2, 2.6, 2.8, 2.11