Unit Conversion/Dimensional Analysis

8/11/2019 Unit Conversion/Dimensional Analysis

1/16

LecturePLUS Timberlake 1

Chapter 1

Measurements

Problem Solving Using Conversion

Factors/Dimensional Analysis


2/16


Initial and Final Units

A person has a height of 2.0 meters. What is that

height in inches?

Initial unit = m Final unit = _______

1 m = 39.37 in


3/16


How many minutes are in 2.5 hours?

Initial unit

2.5 hr

Conversion Final

factor unit

2.5 hr x 60 min = 150 min

1 hr

cancel Answer (2 SF)


4/16


Learning Check

A rattlesnake is 2.44 m long. How long is the

snake in cm?

1) 2440 cm

2) 244 cm

3) 24.4 cm


5/16


6/16


Learning Check

How many seconds are in 1.4 days?

Unit plan: days hr min seconds

1.4 days x 24 hr x ??

1 day


7/16


Solution CF2

Unit plan: days hr min seconds

2 SF Exact

1.4 day x 24 hr x 60 min x 60 sec

1 day 1 hr 1 min

= 1.2 x 105 sec


8/16


Unit Check

What iswrongwiththe following setup?

1.4 day x 1 day x 60 min x 60 sec

24 hr 1 hr 1 min


9/16


Unit Check

1.4 day x 1 day x 60 min x 60 sec

24hr 1 hr 1 min

Units = day2

/hr2

Not the f inal uni t needed


10/16


Learning CheckAn adult human has 4650 mL of blood. How

many gallons of blood is that?

Unit plan: mL qt gallon

Equalities: 1 quart = 946 mL

1 gallon = 4 quarts

Your Setup:


11/16


Solution

Unit plan: mL qt gallon

Setup:4650 mL x 1 qt x 1 gal = 1.23 gal

946 mL 4 qt

3 SF 3 SF exact 3 SF


12/16


Steps to Problem Solving

Read problem

Identify data

Write down a unit plan from the initial unit

to the desired unit

Select conversion factors

Change initial unit to desired unit

Cancel units and check

Do math on calculator

Give an answer using significant figures


13/16


Learning Check

If the ski pole is 3.0 feet in length, how long is

the ski pole in mm?


14/16


Solution

3.0 ft x 12 in x 2.54 cm x 10 mm =

1 ft 1 in. 1 cm


15/16


16/16

Documents

Unit Conversion/Dimensional Analysis