1. Chapter 4

2.  List several useful problem solving skills  Deductive reasoning Deductive  Inductive reasoning Inductive  A three step problem solving approach, (ACE)  Analyze  Calculate  Evaluate

3.  Conversion Factors  Must be constructed from equivalent measurements  Example: 1 dollar equals 4 quarters, ($1 = 4 x 25 cents)  Equal in value  Example: 1 meter = 100 centimeters  A small number of large items = a large number of small items  The meter stick has 100 cm or 1000 millimeters or 10 decimeters  All are valid and equivalent measurements  100cm/1meter converts from meters to cm  1 meter/100 cm converts from cm to meters

4.  Dimensional Analysis is a way to analyze and solve problems using the UNITS or dimensions of the measurements  If each person at a party will eat 2 hamburgers, how many will you need for 18 people? 36 HB  2 HB/1 person x 18 person = 36 HB  If each HB has 2 pickles, how many will you need?  36 HB x 2 pickles/1 HB = 72 pickles  If 1 jar of pickles has 110 pieces, how many HB could be made?

5.  Multi Step Problems  Miles to Feet to Yards: If you went 3.5 miles, how many yards is that?  What you need to know:  1 mile = 5280 feet  1 yard = 3 feet  How to convert, (the units miles and feet cancel)  3.5 miles x 5280 feet /1mile x 1yard/3 feet = ___ yards  You get an answer in yards -> 6160 yards

6.  Converting Complex Units  Many measurements are expressed as a ratio of units, (miles per hour, Kilometers per second,…)  Convert 10 mi/hr to km/sec, (the units of same color cancel)  10 mi/ hr x 1 km/.55 mi x 1 hr /60 min x 1 min / 60 sec= So you are left with units of km/sec The math is 10 x 1 x 1 x 1 /.55 x 60 x 60 = The answer is 0.005 km/sec