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Answer Key to Study Guide and Practice Problems to Help Further Prepare for the Quiz on Physics- Chapter 1Mrs. AshleySignificant Figures: How many significant figures in the following problems?1. 205.0 Kilograms + 23.0 Kilograms Three significant figures2. 670 meters - 0.430 meters Three significant figures3. 4.3 x 103 X 5.35 x 105 Two significant figures4. 752.030 meters Six significant figures5. 0.003 grams One significant figure6. 23,434,251.0 Eight significant figuresRules for significant figures: Non zero numbers are always significant; final or ending zeros written to the right of the decimal point are significant; zeros written between significant figures are significant; zeros written to the right of the decimal point to hold the placement for the decimal point are not significant (0.003 has only one significant digit); If there is a zero alone to the right of a decimal point it is considered significant as above (200.0 has four significant figures); zeros written before the decimal point that are not between significant figures are not significant (2450 has three significant figures)Significant figures indicate the precision to which the number is known. Writing the number in scientific notation can clarify the exact number of significant figures in a number. When two or more numbers are added, the result is as precise as the least precise of the quantities.When quantities are multiplied or divided, the result has the same number of significant figures as the quantity with the smallest number of significant figures.In a series of calculations, rounding to the correct number of significant figures should be done only at the end, not at each step. You can keep at least two extra significant figures in calculations, then round at the end.Scientific Notation: write each of the following in scientific notation.7. 2,343,560 2.343560 x 1068. .0345 3.45 x 10-29. 245.670 2.45670 x 102Write each of the scientific notation numbers in conventional decimal notation:10. 3.245 x 10-4 0.000324511. 7.45 x 108 745,000,000Solve the problems below and put your answer in scientific notation and with significant figures.12. 3.45 x 100 - 5.6 x 10-2 = 3.45 - 0.056 = 3.394 x 10-2 = 3.4 x 10-213. 3.45 x 104 7.9 x 103 = .4367088 x 101 = 4.4 x 10014. 6.59 x 105 8.2 x 10-8 = 54.038 x 10-3 = 5.4 x 10-215 Express (2.2 × 106)-1/2 in scientific notation.2.2 x 103When adding two or more quantities that are written in scientific notation with different powers of 10, first rewrite them with the same power of ten. Then write the answer using the least number of significant figures in the problem.SI units: Know the base units and what they measure as well as their symbols: meter for length (m); kilogram for mass (k); second for time (s); ampere for electric current (A); Kelvin for temperature (K); mole for amount of a substance (mol); and candela for luminous intensity (cd).Know the following units for converting: tera- (T) 1012; giga- (G) 109 ; mega- (M) 106 ; kilo- (k) 103 ; centi- (c) 10-2 ; milli- (m) 10-3 ; micro- () 10-6 ; nano- () 10-9Problems changing units:16. Michael, an exchange student from France, is studying in the United States. He wishes to buy a new pair of jeans, but the sizes are all in inches. He does remember that 1m =3.28 ft and the 1ft - 12 in. If his waist size is 82 cm, what is his waist size in inches?82 cm 1m/100cm 3.28 ft/1m 12 in/1ft = 32 in17. A beaker of water contains 255 mL of water and one liter is 1000 cm3 What is the volume of water in cubic centimeters? What is the volume in cubic meters?255mL 10-3 L/1mL 1000 cm3 = 255 cm3255 cm3 (1m/100cm)3 = 255 cm3 x 1m/100cm 1m/100cm 1m/100cm = 255 x 1 m3/ 1000000 cm3 = 2.55 x 10-4 m318. Using a digital balance the mass of a certain piece of wood is read as 12.946 g. Thinking in terms of accuracy and significant figures, what value would you record on your data sheet if the balance is accurate to one-tenth of a gram?12.9 g19. A sprinter can run at a top speed of 0.32 miles per minute. Express her speed in a.)meters/sec b.) mi/ha.) 0.32 mi/min 1 min/ 60 s 1 km/ .6214 mi 1000 m/ 1 km = 8.58 m/s = 8.6 m/sb.) 0.32 mi/min 60min/hr = 19.2 mi/hr = 19 mi/hr20. A cell member is 7.0 m thick. How thick is it in inches?7.0 m 1 m/ 109m 1 in/2.54cm 100 cm/ 1 m = 2.8 x 10-7in ................
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