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 Oct 9th 2017, 02:40 AM #1 Junior Member   Join Date: Oct 2017 Location: Boston Posts: 5 need help in physics 1- State how many significant figures are proper in the results of the following calculation: (15.1)(0.20 - 30.05 + 170.2) 2- Cos 126.39° 3- Soccer fields vary in size. A large soccer field is 90.3 m long and 83.1 m wide. What is its smallest dimension in inches? (Assume that 1 meter equals 3.281 feet.) 4- Solve: (1.6 x 102) / (3.5 x 103) 5- Solve: (4 x 10-1)2 6- Sin 109.65° Last edited by topsquark; Oct 9th 2017 at 11:06 AM. Reason: Too many questions
 Oct 11th 2017, 08:11 AM #2 Senior Member     Join Date: Jun 2016 Location: England Posts: 264 Basically you should not include any more precision in the answer than is available in the question. So if you have: A = 1.2 / 2.3 the answer should not be quoted as 0.52173913 If we are rounding off the two input values, they might be anything from 1.15 to 1.25 and 2.25 to 2.35 Thus A can be anything from 1.15 / 2.35 = 0.4893617... up to 1.25 / 2.25 = 0.555555... So in this case we can say only say the answer is about 0.52 (+/- 0.03) Note the distinction between significant figures and decimal places. In my example above the input values have 1 decimal place, but two significant figures, (the output value has 2 significant figures and 2 decimal places). It is unlikely that the input values are both at the extreme edges, There is quite a sophisticated statistical analysis for error estimation (and thus provision of suitable numbers of significant figures) However, as a pretty reliable rule of thumb, the number of significant figures in the answer should not exceed the (minimum) number of significant figures in the question. So the answer to A = 1.20 / 2.30 would be 0.522 __________________ ~\o/~ Last edited by Woody; Oct 12th 2017 at 05:29 AM.

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