{"id":170,"date":"2018-03-20T13:38:17","date_gmt":"2018-03-20T13:38:17","guid":{"rendered":"https:\/\/books.compclassnotes.com\/rothphys110\/?p=170"},"modified":"2021-04-24T03:11:57","modified_gmt":"2021-04-24T03:11:57","slug":"section-6-5","status":"publish","type":"post","link":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/2018\/03\/20\/section-6-5\/","title":{"rendered":"Chapter 6: Energy"},"content":{"rendered":"\n

6.5 Problem solving steps<\/h2>\n\n\n\n

6.5.1 Problem solving in general<\/h3>\n\n\n\n

We now have several different ways of determining the energy of some physical system\u2014how do we actually use this knowledge to solve problems?<\/p>\n\n\n\n

Solving physics problems is not on simply memorizing formulas. Instead, we focus on understanding a process. You will encounter different sorts of problems, where you will need to use different principles. We\u2019re starting with conservation of energy, but later on we\u2019ll encounter conservation of momentum (ch. 7), Newton\u2019s second law (ch. 9 and ch. 11), and kinematics (ch. 12). Very generally\u2014for just about any problem you encounter\u2014you\u2019ll follow these three basic steps:<\/p>\n\n\n\n

  1. Draw a picture.<\/li>
  2. Apply a fundamental law or principle of physics.<\/li>
  3. Solve.<\/li><\/ol>\n\n\n\n

    Drawing a picture helps you visualize the situation that is presented in a problem. You should label your drawing with things like arrows to indicate motion, and variables representing physical quantities. Sometimes you\u2019ll find drawing a sequence of pictures to be useful. Your drawing does not have to be an artistic masterpiece; it just needs to serve as a bridge between the verbal and mathematical explanations of a situation.<\/p>\n\n\n\n

    Recognizing which fundamental law or principle is one of the most important parts of solving the problem. This is your mathematical description of the situation and your starting point for actually solving quantitatively.<\/p>\n\n\n\n

    The final step is where you carry out the algebra required to get to an answer. You\u2019ll always work from very general (a fundamental<\/em> law or principle) to specific (what is going on in this particular<\/em> situation). Remember to work symbolically, and save adding numbers until the very last step.<\/p>\n\n\n\n

    6.5.2 Solving problems with energy conservation<\/h3>\n\n\n\n

    Section 6.1.1 gives us a mathematical statement of conservation of energy:<\/p>\n\n\n\n

    E<\/em>i<\/em><\/sub> = E<\/em>f<\/em><\/sub><\/p>\n\n\n\n

    When we\u2019re solving problems where energy is converted from one form to another, this is the fundamental law that we\u2019ll apply to solve the problem.<\/p>\n\n\n\n

    Example<\/h4>\n\n\n\n\n