Chapter 8

Factor – Label Method

Part 1

24 in. = ___ ft.

You have just used a conversion factor.

Conversion Factor

A relationship between two units

expressed in fractional form

Conversion Factors• A conversion factor is a ratio:

12 inches or 1 foot

1 foot 12 inches

Factor Label Method

Method of converting from one unit to another using

conversion factors

24 in. = ___ ft.

We can solve this problem using factor label method.

Prefix Symbol Value Power Use

Giga G 1,000,000,000 109 Gigabyte

Mega M 1,000,000 106 Megawatt

kilokilo kk 1,0001,000 101033 kilometerkilometer

deci d 0.1 10-1 decigram

centicenti cc 0.010.01 1010-2-2 centimetercentimeter

millimilli mm 0.0010.001 1010-3-3 millilitermilliliter

micro 0.000001 10-6 microsecond

nano n 0.000000001 10-9 nanometer

Prefixes in the Metric SystemPrefixes in the Metric System

An Example of a Metric Conversion Factor

• 1000 m = 1 km

km1

1000m

1000m

km1

This can be written as the factors ...

An Example Problem …

• Convert 10.83 cm to meters using the Factor Label Method.

Convert 10.83 cm to meters

10.83cm

Convert 10.83 cm to meters

10.83cm

cm

Convert 10.83 cm to meters

10.83cm

cm

m

Convert 10.83 cm to meters

10.83cm

cm

m0.01

Convert 10.83 cm to meters

10.83cm

cm

m0.01= 0.1083 m

Convert 152dg to mg

152dg

Convert 152dg to mg

152dg

dg

Convert 152dg to mg

152dg

dg

g

Convert 152dg to mg

152dg

dg

0.1g

Convert 152dg to mg

152dg

dg

0.1g

Convert 152dg to mg

152dg

dg

0.1g

g

Convert 152dg to mg

152dg

dg

0.1g

g

mg

Convert 152dg to mg

152dg

dg

0.1g

g

mg

0.001

Convert 152dg to mg

152dg

dg

0.1g

g

mg

0.001= 15,200mg

Convert 6896s to weeks

6896s

Convert 6896s to weeks

6896s60smin

Convert 6896s to weeks

6896s60smin

60minhr

Convert 6896s to weeks

6896s60smin

60minhr

24hrday

Convert 6896s to weeks

6896s60smin

60minhr

24hrday

7 daysweek

Convert 6896s to weeks

6896s60smin

60minhr

24hrday

7 daysweek

= 0.01140 weeks

Convert 150.0 mg/hr to cg/year

Convert 150.0 mg/hr to cg/year

150.0mg

hr

Convert 150.0 mg/hr to cg/year

150.0mg

hr

0.001g

mg

Convert 150.0 mg/hr to cg/year

150.0mg

hr

0.001g

mg 0.01g

cg

Convert 150.0 mg/hr to cg/year

150.0mg

hr

0.001g

mg 0.01g

cg 24 hr

day

Convert 150.0 mg/hr to cg/year

150.0mg

hr

0.001g

mg 0.01g

cg 24 hr

day

365 days

year= 131,400 cg/year

How many minutes does it take light to reach us from the sun which is

93,000,000 miles distant.

• The following information will be useful:– speed of light = 3.0 x 108 m/s – 1km = 0.6214 mi