2.  AKA Unit conversions Dimensional Analysis

3.  Use conversion factors to solve math problems  When you divide a number by itself, that fraction is equal to one  A conversion factor is a fraction that is equal to one. It is formed from a valid relationship between numbers with units.

4. Ex: 1 = 1 because 1=1 1 Ex: 4.5 = 1 because 4.5=4.5 4.5 So… if 1 ft = 12 in then 1 ft = 1 or 12 in = 1 12 in 1 ft If 60 sec. = 1 min then 1 min = 1 or 60 sec = 1 60 sec 1 min Multiplying a number by a conversion factor is the same as multiplying by 1, but it allows you to change units.

5.  Treat units like #s Units cancel like numbers: when the same unit is the numerator and denominator it cancels to one Ex: meter = 1 meter Ex: hours = 1 hours It works with abbreviations too: mL = 1 mL g = 1 g

7. 1. Write the known quantity. 2. Figure out the units you need to end up with. 3. Multiply by conversion factors to get from the original units to the final. 4. Like units cancel top & bottom. 5. NO NAKED NUMBERS!

8.  Start with what you know:  What unit do we need to end with?  What conversion unit(s) do we need to use to solve this problem?  No naked numbers in work or answer!  Cancel the units and multiply the numbers: 3.75 dollars quarters 4 quarters 1 dollar 3.75 dollars 4 quarters 1 dollar = 15.0 quarters

9.  Take out notebook and homework leave on desk.  Attach objectives in notebook  Try to use unit analysis to calculate how many dollars you have if you have 177 nickels? How many inches are in 2.76 ft?

10.  Take out homework for me to stamp  While waiting complete part 1 # 3 using unit analysis (it is ok- and encouraged- to work together as I will be stamping off homework unable to answer many specific questions)  If you have finished this either compare with a partner or help another student.

11. 30 Days 24 hr 1 day =Sec. 60 min 1 hr 60 sec 1 min 2,592,000

12.  There are 2. 54 cm in 1.00 inch Therefore we can use this as a conversion factor  There are 19.32 g of gold in 1.00 cm 3 of gold Therefore we can use this as a conversion factor 2.54 cm 1.00 in 3.0in 3 2.54cm 2.54cm 2.54cm 19.32g = 950 g 1.00 in 1.00 in 1.00 in 1.00 cm 3 19.32 g 1.00 cm 3

13. 1. You are working in a factory and you have 15462 nails that you need to pack and ship. Each box can fit 150 nails and each crate can hold 15 boxes. How many crates will you fill with nails? 2. A runner ran 3680 m. If there are 1.09 yards in one meter and 120. yards in a football field, how many football fields is this?