I

II

III

III. Unit Conversions

CH. 2 - MEASUREMENT

3

3

cm

gcm

A. Dimensional Analysis

The “Factor-Label” Method Units, or “labels” are canceled, or

“factored” out

g

A. 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.

A. Dimensional Analysis

Lining up conversion factors:

1 in = 2.54 cm

2.54 cm 2.54 cm

1 in = 2.54 cm

1 in 1 in

= 1

1 =

B. Conversion Factors

Conversion Factors to Know:

1 in = 2.54 cm

1 mile = 2,580 ft

1 lb = 454 g

1 kg = 2.2 lbs

1 L = 1.06 qt

B. Conversion Factors

mega- 1 M(u) = 106 (u)

deci- 1(u) = 101 d(u)

centi- 1 (u) = 102 c(u)

milli- 1 (u) = 103 m(u)

Prefix Conversion Factor

micro- 1 (u) = 106 (u)

nano- 1 (u) = 109 n(u)

pico- 1 (u) = 1012 p(u)

kilo- k(u) = 103 (u)

BASE UNIT (u) = 100

C. Practice Problems

1) 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

cm in

C. Practice Problems

2) A light bulb requires 0.032 amps to operate. What is this quantity in milliamps?

0.032 A 103 mA

1 A= 32 mA

A mA

C. Practice Problems

3) How many milliliters are in 1.00 quart of milk?

1.00 qt 1 L

1.057 qt= 946 mL

qt mL

1000 mL

1 L

C. Practice Problems

4) A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire?

1.3 m 100 cm

1 m= 86 pieces

cm pieces

1 piece

1.5 cm

C. Practice Problems

5) A road race is 805 dm long. What is the length of the race in kilometers?

805 dm 1 m

102 dm = 8.05 x 10-2 km

1000 km

1 m

dm km

C. Practice Problems

6) The Eagles needs 550 cm for a 1st down. How many yards is this?

550 cm 1 in

2.54 cm= 6.0 yd

cm yd

1 ft

12 in

1 yd

3 ft

C. Practice Problems

7) How many liters of water would fill a container that measures 75.0 in3?

75.0 in3 (2.54 cm)3

(1 in)3= 1.23 L

in3 L

1 L

1000 cm3

C. Practice Problems

8) You have 1.5 pounds of gold. Find its volume in cm3 if the density of gold is 19.3 g/cm3.

lb cm3

1.5 lb 1 kg

2.2 lb= 35 cm3

1000 g

1 kg

1 cm3

19.3 g