Presentation on theme: "STARTER Put this number in scientific notation."— Presentation transcript:
1STARTER Put this number in scientific notation. The mass of an electron is :kgPut this number in scientific notation.
2Scientific NotationIf numbers are very large, like the mass of the EarthkgOr very small like the mass of an electron :kgthen standard decimal notation is very cumbersome,so we use scientific notation.
3Scientific Notation Example: 5.9 x 1024 Example: 6.2 x 10-4 A number in scientific notation has two parts:1st part: a number between 1 and 102nd part: 10 to some power.Example: x 10241024 Means move the decimal 24 places to the right.Example: x 10-410-4 Means move the decimal 4 places to the left.
4Examples – Put the number in Scientific Notation Answer: = 3.45 x 105bAnswer: = 3.4 x 10-4
5CalculatorsTo enter a number in scientific notation into a calculator,the most common method is to use the EE button.Example: to enter 1.56 x 104Press: 1.56(EE) Display: 1.56E4In other words, E4 stands for “x 104 “
7Examples Simplify: (2 x 103)(4 x 106) = (2)(4) x 103(106) = 8 x 109
8Significant FiguresHow to count the number of significant figures ina decimal number.Zeros Between other non-zero digits are significant.a has three significant figuresb has five significant figures
9Significant FiguresZeros in front of nonzero digits are not significant:0.892 has three significant figureshas one significant figure
10Significant Figures Zeros that are at the end of a decimal number are significant.57.00 has four significant figureshas seven significant figuresAt the end of a non-decimal number they are not.5700 has two significant figures2020 has three significant figures
11SummaryFor decimal numbers, start from the left and find the 1st nonzero digit.This digit and all others to the right are counted.has 5 sig. figs.For non-decimals, start from the left and find the 1st nonzero digit.This digit and all others to the right are counted until you get to onlyzeros which are not counted.has 5 sig. figs
12Non-Decimal NumbersMajor pain to try to figure out the significant figures – it depends on the number’s history. Don’t Use Them. Use Scientific Notation to express any number to a desired amount of significant figures. Example: Express 234 to 4 sig. figs x 102
13Practice Find the number of significant figures. 2.00450 .0034050 1450 6 sf’s.5 sf’s3 sf’s4 sf’s
14Significant Figures After Division and Multiplication After performing the calculation, note the factor that has the least number of sig figs. Round the product or quotient to this number of digits.3.22 X 2.1 = 6.836.5/3.414 = 10.7
15Significant Figures Addition or subtraction with significant figures: The final answer should have the same number of digits to the right of the decimal as the measurement with the smallest number of digits to the right of the decimal.Ex:= 103.2
18Conversions Converting From One System of Units to Another You will need a conversion factor like ( 1 meter = 3.28 ft).It can be used two ways:(1m/3.28ft) or ( 3.28ft/1m)Multiply your given dimension by the conversion factor to obtain the desired dimension.How many feet in 2 meters? m (3.28ft/m) = 6.56 feetHow many meters in 10 feet? ft(1m/3.28ft) = 3.05 meters
19Converting AreasTo convert areas, you must square the conversion factor.Conversion factor: 1 inch = 2.54cmA page is 8.5 inches by 11 inches. What is the area in square centimeters?The area in square inches is 94 in2. So……94 in2 = __________cm294 in2(2.54cm/1 in)2 = 94(6.45 cm2) / (1 in2) = 606 cm2
20Converting VolumesTo convert volumes, you must cube the conversion factor.A cubic foot is how many cubic inches?Conversion factor: 1 foot = 12 inches1 ft 3 ( 12 in/ 1 ft)3 = 1 ft 3 ( 123 in3/ 13 ft3) = 1728in3
22Examples 12nm = 12 x 10-9 m Finished. Change 12nm to meters. n = x 10-9 so replace it:12nm = 12 x 10-9 m Finished.
23Examples 250g ( 1 kg/1x103 g) = .250 kg Change 250 grams to kilograms. 1 kg = 1x103 gram250g ( 1 kg/1x103 g) = kg
24Example Use the fact that c = x 10-2 A metal plate is 12.0cm by 4.0cm. What is the area in square meters?Use the fact that c = x 10-2Area = (12.0cm)(4.0cm) = (12.0x10-2m)(4.0 x 10-2 m) = 4.8 x 10-3m2
25Exit Physics uses the S.I. metric system, also known as the “mks” system.In this system, what are the base units formass, time, and length?