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Section 5.3 09/24/07 Problem Solving and Unit Conversions DIMENSIONAL ANALYSIS Section 5.3 Problem Solving and Unit Conversions Objectives 1. To learn how dimensional ______________ can be used to solve problems 2. To learn to ___________ from one metric unit to another 3. To learn to convert between _______ units and standard _____ units 4. To practice using problem solving techniques Section 5.3 Problem Solving and Unit Conversions A. Tools for Problem Solving • Be systematic • Ask yourself these questions Section 5.3 Problem Solving and Unit Conversions A. Tools for Problem Solving Converting Units of Measurement • We can convert from one ___________ of units to another by a method called _____________________ using conversion factors. • Unit1 _______________________ = Unit2 Section 5.3 Problem Solving and Unit Conversions A. Tools for Problem Solving Converting Units of Money • Conversion factors are built from an ________________________which shows the ______________ between the units in different systems. • Conversion factors are ____________ of the two parts of the equivalence statement that relate the two units. Section 5.3 Problem Solving and Unit Conversions Using Simple Dimensional Analysis • Example 1: You have 12 nickels and to save pocket space you want to trade them to your friend for dimes. How many dimes would you have? Section 5.3 Problem Solving and Unit Conversions Using Simple Dimensional Analysis • Example 2: It takes you 2.6 days to travel to a remote get away in California. How many seconds will it take you? Section 5.3 Problem Solving and Unit Conversions Using Dimensional Analysis • Use the same method to convert metric to metric. How many centimeters are in 2.5 meters? Section 5.3 Problem Solving and Unit Conversions A. Tools for Problem Solving Converting Units of Measure 2.85 cm = ? in. 2.85 cm conversion factor = ? in. Equivalence statement _______ cm = 1 in. Possible conversion factors Does this answer make sense? Section 5.3 Problem Solving and Unit Conversions ***THINGS TO REMEMBER when doing Conversions 1. Take what you are given -i.e. What is/are my ____________? 2. Determine what units want to convert to -i.e. What is/are the unit(s) I want in my final answer (what are the _________________)? 3. Find the ___________________________. -To convert between any units you must have _____________________ 4. What is/are the possible _____________ factors? Section 5.3 Problem Solving and Unit Conversions ***THINGS TO REMEMBER when doing Conversions cont… 5. Choose the conversion factor that fits your __________. 6. Conversion factor should be a __________. 7. The unit you want to get rid of should be on the ______ (i.e. in the denominator) to cancel out (or on the top depending on your conversion) 8. The ending unit should be on the ________ (i.e. in the numerator) -The answer should make sense if you got to the right unit(s) 9. Check you Sig. Figs. -Remember the EXACT NUMBERS Sig. Figs. Rule??? Section 5.3 Problem Solving and Unit Conversions A. Tools for Problem Solving Tools for Converting from One Unit to Another Step 1 Find an equivalence statement that relates the 2 units. Step 2 Choose the conversion factor by looking at the direction of the required change (cancel the unwanted units). Step 3 Multiply the original quantity by the conversion factor. Step 4 Make sure you have the correct number of significant figures.