Using Dimensional Analysis to Organize Your Work

USING DIMENSIONAL ANALYSIS TO ORGANIZE YOUR WORK 

There are a variety of problem-solving strategies that you will use as you prepare for and take the AP test. Dimensional analysis, sometimes known as the factor label method, is one of the most important of the techniques for you to master. Dimensional analysis is a problem-solving technique that relies on the use of conversion factors to change measurements from one unit to another. It is a very powerful technique but requires careful attention during setup. The conversion factors that are used are equalities between one unit and an equivalent amount of some other unit. In financial terms, we can say that 100 pennies is equal to 1 dollar. While the units of measure are different (pennies and dollars) and the numbers are different (100 and 1), each represents the same amount of money. Therefore, the two are equal. Let s use an example that is more aligned with science. We also know that 100 centimeters are equal to 1 meter. If we express this as an equation, we would write  

You only need to worry about these on the free-response portion of the test. On the multiple-choice portion, they do not try to trick you by having two answers that differ only by the number of significant digits. 

While you are completing the calculation, checkto make sure that all units are canceling. If they do not cancel, it is a warning that you have probably madeanerrorin the setup orthe solution of the problem. 

Since these represent the same distance, the values can be thought of as equivalent. Therefore, we can say that  

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Using dimensional analysis to organize your work... 

Using Dimensional Analysis to Organize Your Work... 

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