Headlines
- Draw picture to better understand problem
- Write down knowns and unknowns
- Pick equation
- Transform Equation
- Very last step - plug in numbers and units
Details
1. READ THE ENTIRE PROBLEM CAREFULLY AND MAKE A SKETCH
Read through the entire problem completely before you start to write anything down. A sketch of the problem situation will help you to clarify the ideas of the problem. If you can't visualize the situation, you might be missing some important concepts.
2. LIST THE GIVEN INFORMATION AND IDENTIFY THE UNKNOWN QUANTITY ASKED FOR IN THE PROBLEM.
Write down each magnitude (number and units) that is given and identify it with the appropriate letter. For example, " a time of six seconds" is listed as "t = 6 sec".
It is important to use the letter symbol that will appear in the equations. For example, if a problem asks you to find " how long it takes" for an event to occur, you would write " t = ?"".
3. FROM YOUR LIST OF EQUATIONS, SELECT THE EQUATION THAT RELATES THE UNKNOWN QUANTITY TO THE GIVEN INFORMATION. REWRITE THE EQUATION, IF NECESSARY, TO SOLVE FOR THE UNKNOWN QUANTITY.
For example, if you know the velocity (v) of an object and the distance it has traveled (d), and you wish to find the time required to travel that distance (t), you would choose the equation that uses all three of these variables: t = dv.
The unknown (in this case, t) should appear alone on the left of the equal sign in your working equation. In the example above, if the unknown was the velocity, the equation would be rewritten to read: v = dt.
4. SUBSTITUTE THE KNOWN INFORMATION IN THE WORKING EQUATION, INCLUDING ALL UNITS.
If you are solving for the velocity in step 3, and the distance is 12 meters ("d = 12 m") and it took 6 seconds ("t = 6 s"), then we would write (after "v = dt"),v = 12 m6 s.
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5. SOLVE THE EQUATION, INDICATING THE CANCELLATION OF UNITS, AND CIRCLE YOUR ANSWER.
For example, v = 12 m6 s = 2 ms. The units combine (and can cancel) just like numbers. Notice that "meters per second" is a correct unit for velocity. Check your answer to see that it has the correct units. For example, if you find that the weight of an object is in units of "square feet", then an error has occurred.
Also, check the magnitude of your answer; if it is obviously physically impossible, go back and look for an error. For example, if you find the speed of a car to be 4000 mph, the answer is not reasonable. Make sure you circle your answer to avoid confusion.
Each chapter is composed of the subject material, problems to work, and an experiment relating to the material. Solutions to the work problems, units, conversions, constants, useful equations and techniques are provided in the appendices. Space is provided in this book for your notes and work problem solutions. As you perform each experiment, you will record your data in this book. Your work group will submit a separate, formal report to the instructor for evaluation. Do not remove pages from this book, since you are allowed to use it as a reference during examinations.