PHYSICS H90 Lecture 2: physicswk1lec2
10 Jan 2019
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Little work -> know what to expect & provide reality check on more precise answers. Exact answers are great, but often, a reasonable estimate is even better. Especially powerful when used in conjunction with dimensional analysis. Components of a good back of the envelope calculation: Get an estimate, with assumptions stated clearly. (sometimes) determine how your answer scales with input parameters. Use the fact that two sides of an equation must have the same dimensions. Checking that the units agree can help avoid mistakes, eliminate multiple choice answers, etc. Can be used to find an approx. answer with very little work & to understand how the answers depend on input parameters (scaling) Back of the envelope calculations, graphs, data, how to lie with statistics. Consider the big pile of paper -> start with something we (roughly) know: 500 pages is about 2 inches high. Know that trump is about 80 inches tall.
