1. 7.3: Analyze Units Objective:
Learn to use one or more conversion factors to solve rate problems.
Palg

2. Review 1 foot = 12 inches 1 yd = 3 feet 1 meter = 100 centimeters
1 mile = 5280 feet
1 meter = 100 centimeters
1 pound = 16 ounces
1 minute = 60 seconds
1 hour = 60 minutes

3. Conversion Factors Problem solving skills….
Dimensional analysis or unit analysis, is used to convert from one unit to another unit.
To convert units, multiply by one or more ratios of equal quantities called conversion factors.
To convert inches to feet, you would use the ratio below as a conversion factor.
1 ft = 12 in ft This fraction reduces to 1.
12 in. Why?

4. Finding Conversion Factors
Example 1: Find the appropriate factor for each conversion.
A) Feet to yards
What do we know??? 1 yd = 3 feet
Write a conversion factor that is equivalent to 1:
why? Because
B) Pounds to ounces
What do we know??? 1 lb = 16 oz

5. Using Conversion Factors to Solve Problems
Example 2: The average American uses 580 pounds of paper per year. Find the number of pounds of paper the average American uses per month, to the nearest tenth.
Set up a ratio: and we want to convert to months.
What is the relationship between months and a year?
1 yr = 12 months
This can be used as a conversion factor:
48.3 lb/mo

6. Using Conversion Factors to Solve Problems
Example 3: A car traveled 60 miles on a road in 2 hours. How many feet per second was the car traveling?
Set up a ratio: and we want to convert to feet per second.
What is the relationship between hours and seconds, miles and feet?
1 hr = 60 secs 1 mi = 5280 ft
Both can be used as a conversion factor: ;

7. Using Conversion to Solve Problems
Example 4: A strobe lamp can be used to measure the speed of an object. The lamp flashes every 1/100 of a second, or 0.01 secs. A camera records the object moving 52 cm between flashes. How fast is the object moving in m/s?

8. Using Conversion to Solve Problems
Example 5: The rate 1 knot equals 1 nautical mile per hour. One nautical mile is 1852 meters. What is the speed in kilometers per hour of a ship traveling at 5 knots?

9. HOMEWORK
7.3 hw pg. 352: 2 – 22 (evens)