Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

be used in engineering formulas when using U.S. Customary units. The units of temperature

in the U.S. Customary system are identical to the BG system, which we discussed earlier.

Finally, by comparing the units of mass in the BG system (that is one slug) to the U.S.

system pound mass, we note 1 slug32.2 lbm. For those of us who might be slightly massive

(overweight), it might be wiser to express our mass in slugs rather than in pound mass or

kilogram. For example, a person who has a mass of 200 lbmor 90.7 kg would sound skinny if

he were instead to express his mass as 6.2 slugs. Note that 200 lbm90.7 kg6.2 slugs, and

therefore, he is telling the truth about his mass! So you don’t have to lie about your mass; knowl-

edge of units can bring about instant results without any exercise or diet!

Examples of SI and U.S. Customary units used in our everyday lives are shown in

Tables 6.4 and 6.5, respectively. The conversion factors for the fundamental and derived

dimensions commonly encountered in engineering are shown in Table 6.6. Detailed conversion

tables are also given on the back endpapers of this book.

6.2 Systems of Units 137

TABLE 6.4 Examples of SI Units in Everyday Use

Examples of SI Unit Usage SI Units Used

Camera film 35 mm

Medication dose such as pills 100 mg, 250 mg, or 500 mg

Sports:

swimming 100 m breaststroke or butterfly stroke

running 100 m, 200 m, 400 m, 5000 m, and so on

Automobile engine capacity 2.2 L (liter), 3.8 L, and so on

Light bulbs 60 W, 100 W, or 150 W

Electric consumption kWh (killo-Watt-hour)

Radio broadcasting signal frequencies 88 –108 MHz (FM broadcast band)

0.54 –1.6 MHz (AM broadcast band)

Police, fire 153 –159 MHz

Global positioning system signals 1575.42 MHz and 1227.60 MHz

TABLE 6.5 Examples of U.S. Customary Units in Everyday Use

Examples of U.S. Customary Unit Usage U.S. Customary Units Used

Fuel tank capacity 20 gallons or 2.67 ft^3

(1 ft^3 7.48 gallons)

Sports (length of a football field) 100 yd or 300 ft

Power capacity of an automobile 150 hp or 82500 lbft /s

(1 hp550 lbft /s)

Distance between two cities 100 miles

(1 mile5280 ft)

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