1. LecturePLUS Timberlake1 Chapter 1 Measurements Problem Solving Using Conversion Factors and SF’s

2. 2 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/mL. If a person lost 0.30 pints of blood at 18°C, how many ounces of blood would that be? Initial (given) = pintsFinal (unk) unit = ___

3. LecturePLUS Timberlake3 How many minutes are in 2.5 hours ? Initial or Given unit 2.5 hr Conversion Final or Unknown factor unit 2.5 hr x 60 min = 150 min 1 hr cancel Answer (2 SF)

4. LecturePLUS Timberlake4 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. LecturePLUS Timberlake5 Solution A rattlesnake is 2.44 m long. How long is the snake in cm? 2)244 cm 2.44 m x 100 cm = 244 cm 1 m

6. LecturePLUS Timberlake6 Learning Check How many seconds are in 1.4 days? Unit plan: days hr min seconds 1.4 days x 24 hr x ?? = ? sec 1 day

7. LecturePLUS Timberlake7 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 10 5 sec

8. LecturePLUS Timberlake8 Unit Check What is wrong with the following setup? 1.4 day x 1 day x 60 min x 60 sec 24 hr 1 hr 1 min

9. LecturePLUS Timberlake9 Unit Check 1.4 day x 1 day x 60 min x 60 sec 24 hr 1 hr 1 min Units = day 2 /hr 2 Not the final unit needed

10. LecturePLUS Timberlake10 Learning Check An 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. LecturePLUS Timberlake11 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. LecturePLUS Timberlake12 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. LecturePLUS Timberlake13 Learning Check If the ski pole is 3.0 feet in length, how long is the ski pole in mm?

14. LecturePLUS Timberlake14 Solution 3.0 ft x 12 in x 2.54 cm x 10 mm = ? mm 1 ft 1 in. 1 cm

15. LecturePLUS Timberlake15 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?

16. LecturePLUS Timberlake16 Initial 8450 ft x 12 in. x 2.54 cm x 1 m 1 ft 1 in. 100 cm x 1 min x 60 sec = 2400 sec 65 m 1 min final (2 SF) Solution