1. Chapter 8 Measurements Problem Solving Using Conversion Factors

2. Initial and Final Units 1. A person has a height of 2.0 meters. What is that height in inches? Initial unit = mFinal 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 = pintsFinal unit = _______

3. 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. 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. 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. 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. Solution CF2 Unit plan: days hr min seconds 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. 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. 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. 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. 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. 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. Learning Check If the ski pole is 3.0 feet in length, how long is the ski pole in mm?

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

15. 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. 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 Solution