Chapter 1 Measurements Problem Solving Using Conversion Factors

Chapter 1 Measurements Problem Solving Using Conversion Factors and SF’s Lecture. PLUS Timberlake 1

Initial and Final Units 1. A person has a height of 2. 0 meters. What is that height in inches? Initial (given) unit = m Final (unknown)unit = ____? __ 2) Blood has a density of 0. 05 g/m. L. If a person lost 0. 30 pints of blood at 18°C, how many ounces of blood would that be? Initial (given) = pints Final (unk) unit = ___ 2

How many minutes are in 2. 5 hours? Initial or Given unit 2. 5 hr Conversion factor 2. 5 hr x 60 min 1 hr cancel Final or Unknown unit = 150 min Answer (2 SF) Lecture. PLUS Timberlake 3

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 Lecture. PLUS Timberlake 4

Solution A rattlesnake is 2. 44 m long. How long is the snake in cm? 2) 244 cm 2. 44 m x 100 cm 1 m = 244 cm Lecture. PLUS Timberlake 5

Learning Check How many seconds are in 1. 4 days? Unit plan: days hr 1. 4 days x 24 hr x 1 day min seconds ? ? = ? sec Lecture. PLUS Timberlake 6

Solution CF 2 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 Lecture. PLUS Timberlake 7

Unit Check What is wrong with the following setup? 1. 4 day x 1 day 24 hr x 60 min 1 hr Lecture. PLUS Timberlake x 60 sec 1 min 8

Unit Check 1. 4 day x 1 day 24 hr Units = day 2/hr 2 x 60 min 1 hr x 60 sec 1 min Not the final unit needed Lecture. PLUS Timberlake 9

Learning Check An adult human has 4650 m. L of blood. How many gallons of blood is that? Unit plan: m. L qt Equalities: 1 quart = 946 m. L 1 gallon = 4 quarts gallon Your Setup: Lecture. PLUS Timberlake 10

Solution Unit plan: m. L Setup: 4650 m. L x 3 SF 1 qt 946 m. L 3 SF qt gallon x 1 gal 4 qt exact = 1. 23 gal Lecture. PLUS Timberlake 3 SF 11

Steps to Problem Solving n n n n 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 Lecture. PLUS Timberlake 12

Learning Check If the ski pole is 3. 0 feet in length, how long is the ski pole in mm? Lecture. PLUS Timberlake 13

Solution 3. 0 ft x 12 in 1 ft x 2. 54 cm x 10 mm = 1 in. 1 cm Lecture. PLUS Timberlake ? mm 14

Learning Check If your pace on a treadmill is 65 meters per minute, how many seconds will it take for you to walk a distance of 8450 feet? Lecture. PLUS Timberlake 15

Solution Initial 8450 ft x 12 in. 1 ft x 1 min 65 m x 2. 54 cm 1 in. x 60 sec 1 min x 1 m 100 cm = 2400 sec final (2 SF) Lecture. PLUS Timberlake 16