Mr. Burkholder Ch 1 PowerPoint Notes

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Mr. BurkholderCh 1 PowerPoint Notes
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Scientific notation is a way of expressing a
value as the product of a number between 1 and 10
and a power of 10.
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Scientific Notation has 2 parts 1st is a
number from 1 to 9.9. 2nd is x10 to a power.
First must contain only significant figures.Ex
6.02 x 1023
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Starting Number1.0 is ok..9 is not ok.10.0 is
not ok. Must be less than 10 and greater than
or to 1.
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Significant FiguresThe starting number must
contain all significant figures and only
significant figures.1.00 x 104 mis different
than1 x 104 m
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Which of these is wrong?1.2 x 104 m1.4 x 10-7
g39 x 104 m/s
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Significant Figures (SF) are the numbers known
precisely plus at least one estimated digit.
Using Sig Figs means that there is uncertainty.
Significant figures are used to show how precise
a measurement is. A measurement with 1 SF (2L)
is not as very precise. Count number of cups on
my desk. Measure length of my pointer as 63 and
64.02 cm and compare. Tell my engineering story
about 44.00 ft steel beams.
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All non zeros are significant
443 3SF 1432 4SF8.4422 5SFHow
many SF does the number 534 have?
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2. Zeros between nonzero digits are SF
20,002 5 SF101 3SF30,421 5SF10,9
21 5SF3004 ? 030040 ?
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  NOTE Starting Zero are not Significant. (Place
holding zeros are not SF (to the
left)) 0.0001 1 SF 0.00045 2
SF5.4 2SF0.000000001 1SF0.00345 ?
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 3. Zeros at the end of a number are not
significant, unless they appear after the decimal
point or if there is a decimal point.
2000 1 SF 2000. 4 SF2040.010 7
SF10 1 SF10. 2 SF 0.00100 ?SF (look
back)
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4. Counted numbers have unlimited SF, no
uncertainty 23 people unlimited
SF144 eggsunlimited SF
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5. Defined quantities (Conversion factors) have
unlimited SF, no uncertainty
1 dozen 12 eggs unlimited SF
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Dimensional Analysis multiplying units together
so that they cancel.Treating units as algebraic
quantities, which can be cancelled.Dimensions
Units
How many nickels are equal to 7.20?
                                                  
                                                  
                             
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Steps for solving problemsStep 1 Analyze the
Problem Put the known on the left. Put the
unknown on the right with an equal sign.
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Steps for solving problemsStep 1 List known and
unknown.Step 2 Solve for the UnknownList
conversion factors and multiply.Conversion
factor units are oftenUnknown units Known
Units
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Steps for solving problemsStep 1 List known and
unknown. Step 2 Multiply by conversion
factors.Step 3 does the answer make sense?
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Conversion factor

• A conversion factor is a multiplier equal to 1
  (top is equal to bottom).
• 1 in 2.54cm (you can construct the following 2
  conversion factors)

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Convert 52.3cm into meters Step 1 List known
and unknown.
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Convert 52.3cm into meters Step 2 Multiply by
conversion factors. Unknown units Known Units
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Convert 52.3cm into metersPut numbers into
conversion factors
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Convert 52.3cm into metersMultiply and/or
divide
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10 meters is how many kilometers?
(What is wrong with this answer?) Ans
SF
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7.20 X _______Q
(for practice,
convert to Quarters first)
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7.20 X _______Q X _______N
Q
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7.20 X _______Q X _______N
N
Q
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7.20 x 4 1 x 5 1 144N
7.20 X _______Q X _______N
N
Q
144 N3 SF
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How many inches are in 2.3 miles?1 mile has
5280ft
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How many days are in 1.7 years?
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Significant Figures in CalculationsYour final
answer can be no more precise then your least
precise measurementRounding off 0.500 round
up0.499 round downex - Round to 3 (SF)345678
3.46 x 10 5 0.4507 4.51 x 10 -1
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Multiplication and Division Round the answer to
have the same SF as the least precise number in
the problem(12 only has 2 SF, answer will only
have 2 SF)12m x 4567m x 123m 6740892 (2 SF)
6.7 x 10 6 m3
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How many Sig Figs will each answer have?25cm x
3.0cm 50g x 5 0.01g 3.00mL
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Addition and Subtraction Line up the decimal
points. Answer has same Sig Fig as biggest
value Sig Fig number.0.45m 2.11111m 13.2m
0.45m 2.11111m 13.2m 15.76111m
correct answer 15.8m
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Addition and Subtraction Example.Someone made
42,512.77 cents. How much more money does he
have?Answer 0. Why?
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Addition and Subtraction Example.Someone made
42,512.77 cents. How much more money does he
have?Answer 0. Why?His name is Bill Gates.
4 Billion Dollars plus 42,512.77 is still 4
Billion Dollars.
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How many SigFigs does the answer have? Finger
Vote. Answer is rounded to 1, Dimes2, or
Pennies3.2.13 3.15 2.33L 1.7L
Shout Out1 x 102m 9.88m
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SI units
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SI units

• SI units use prefixes. Memorize them for the
  test. Look on the inside of your text book for
  1012 to 10-12
• Remember that
• king henry Died by drinking chocolate milk.
• Old k h D b d c m
• New k h da b d c m
• b base unit

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• What are the base units in SI?

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Official Mass kilogram (kg)
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Mass amount of matter in an object kilogram
(kg) We often will use grams for small masses.
New Definition Mass is the resistance to
changes in motion of an object. Bigger masses
take more force to change their motion. Is it
harder to move a tennis ball or a car?
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Official Length meters (m)
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SI units

• Distance is measured in Meters or Kilometers.

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Volume space occupied by an object (L)
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Volume m3 we will often use liter (L)LITER IS
NOT AN SI UNIT!!!
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Density Mass VolumeWhat has more mass 1kg
of feathers or 1kg of rocks?Mass is not equal
to weight!!! Why?
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Time seconds (s)
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Temperature Kelvin (K)
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Density Mass / Volumevolume - amount of space
taken up by an object. Mass - quantity of
matter in an object
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Can the density of an object change?
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Do things expand or contract when they get hot?
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Mathematics and Physics
Section
1.1
Scientific Methods

• A hypothesis can be tested by conducting
  experiments, taking measurements, and identifying
  what variables are important and how they are
  related. Based on the test results, scientists
  establish models, laws, and theories.

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Mathematics and Physics
5 paragraphs of the Scientific Method

• 1. Observations and Testable Question Observe
  and ask a question.
• 2. Hypothesis A prediction.
• 3. Experiment Test hypothesis.
• 4. Analysis and Conclusions Calculations and
  confirm hypothesis.
• 5. Theory and Communicate Discuss the results.