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Dimensional Analysis. Scientific Notation. Scientific notation – way to write very big or very small numbers using powers of 10 3 x 10 8. Superscript. Coefficient. Superscript rules. Numbers greater than 10 = Ex. 257000000000000 Numbers less than 10 = Ex. 0.0000000000000257.
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Scientific Notation • Scientific notation – way to write very big or very small numbers using powers of 10 3 x 108 Superscript Coefficient
Superscript rules • Numbers greater than 10 = • Ex. 257000000000000 • Numbers less than 10 = • Ex. 0.0000000000000257
Rules for Scientific Notation • The coefficient must be between 1.0 and 9.99. • Your coefficient must contain all significant digits. • Move the decimal point as many places as necessary until you create a coefficient between 1.0 and 9.99. • The exponent will be the number of places you move your decimal point. • Moving the decimal to the left makes the number larger = POSITIVE EXPONENT • Numbers greater than 10 always have exponents that are positive. • Moving the decimal to the right makes the number smaller = NEGATIVE EXPONENT • Numbers less than 1.0 always have exponents that are negative
Significant Figures • all the digits that are known precisely plus one last one that is estimated.
Rules for Significant Digits • Every nonzero digit is significant Ex. 24.7 m • Zeros appearing between nonzero digits are significant Ex. 24.07 m
3. Zeros after significant digits are only significant if there is a decimal point Ex. 2470 Ex. 2470.0
4. Zeros in front of numbers are NOT significant, even after a decimal point Ex. 0.0000247 Ex. 0.247 5. When a number is in scientific notation, all numbers in the coefficient are significant Ex. 2.470 x 103
Significant Digits in Calculations • An answer cannot be more precise than the least precise measurement from which it was calculated. • To round off an answer you must first decide how many significant digits the answer should have. • Your calculator DOES NOT keep track of significant digits, you have to do it!
Multiplication & Division • Answer can have no more significant digits than the number in the problem with the fewest significant digits • Ex: 3.24 x 7.689 x 12.0 = 298.94832 • Correct Sig. Figs =
Units of Measurement • SI units – international system of units (very similar to metric system) • Length = meter • Mass = kilogram • Temperature = Kelvin • Time = second
Metric Prefixes • Go in front of metric unit when measuring very big or very small things
Conversions – 1 step Ex 1: A roll of wire is 15m long, what is the length in cm? Ex 2: convert 8.96L to milliliters
1 step cont. • Convert 100 yards to feet • Convert 5 kilometers to miles
Conversions – 2 step • The front board is 500 mm long, how long is it in km? • A football field is 120 yards long, how long is it in miles?
2 step cont. • Convert 525 km to cm • Convert 10000 in to miles
Derived Units • Made by combining SI base units • Volume = cubic meter (m3) • Density = mass/volume • Area = meters squared (m2)
Conversions with derived units • Convert 365 mm3 to m3 • Convert 15.9 cm3/s to L/h