1. Problem Solving Using Conversion Factors
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 cm?
Initial unit = m Final unit = _______
2) Blood has a density of 0.05 g/mL. What is the density in g/L?
Initial = pints Final unit = _______

3. How many minutes are in 2.5 hours?
Initial unit
2.5 hr
Conversion Final
factor unit
2.5 hr x 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) cm
2) 244 cm
3) 24.4 cm

5. Solution A rattlesnake is 2.44 m long. How long is the snake in cm?
2.44 m x 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 2 SF Exact
1.4 day x 24 hr x 60 min x 60 sec
1 day hr 1 min
= 1.2 x 105 sec

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

9. Unit Check 1.4 day x 1 day x 60 min x 60 sec 24 hr 1 hr 1 min
Units = day2/hr2 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 qt x 1 gal = gal
946 mL qt
3 SF SF exact SF

12. Learning Check
If the ski pole is 3.0 feet in length, how long is the ski pole in mm?

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

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 feet?

15. Solution 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 = sec
65 m 1 min final (2 SF)

16. Sample Problem
You have $7.25 in your pocket in quarters. How many quarters do you have?
7.25 dollars quarters
1 dollar
= 29 quarters X

17. Learning Check
A rattlesnake is 2.44 m long. How long is the snake in cm?
a) cm
b) 244 cm
c) 24.4 cm

18. Solution
A rattlesnake is 2.44 m long. How long is the snake in cm?
b) 244 cm
2.44 m x cm = 244 cm
1 m

19. How many seconds are in 1.4 days? Unit plan: days hr min seconds
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

20. Wait a minute!
What is wrong with the following setup?
1.4 day x 1 day x min x 60 sec
24 hr hr min