1. Chapter 1-2: Physics Toolkit

2. Goal of this course . . . NOT to make you a physicist!  IS to . . .
Give you an idea of the way physicists view the world.
Understand and even predict the outcome of events around you.
Be able to pursue career in a technical field.
Be an informed citizen.
Learn to ask questions!

3. a branch of science that involves the study of the physical world
Physics –
a branch of science that involves the study of the physical world
(from electrons to galaxies):
energy, matter, and how they are related
Ex. Waves, sound, light, magnetism, electricity, motion (kinematics), force (dynamics), and much more . . .

4. Tools in our Physics Toolkit
Scientific
Method
System International
(Metric System)
SI Units
Calculators!
Scientific Notation
Significant
Figures
SI Prefixes

5. International System of Units
Abbreviated SI
From the French –
Système international d'unités
Also known as the metric system.
Sometimes called m-k-s system for meters-kilograms-seconds.
The system of measuring units based on ten used around the world.

6. Almost all of modern science is done with the metric system.
SI Units
Almost all of modern science is done with the metric system.
Variable
Unit
Symbol
Length
meters m
Mass
kilograms kg
Time
seconds s
Temperature
Kelvin K
Amount of a Substance
mole
mol
Electric Current
ampere A
Luminous Intensity
candela cd

7. These are quantities that are measured directly => fundamental measurements Other quantities can be found by combining two or more of these direct measurements => derived measurements

8. Measure of time, mass, length, etc. (sec.) (kg) (m)
Fundamental Measurements
Measure of time, mass, length, etc.
(sec.) (kg) (m)
Thus the SI units are also called the Fundamental Units.
Derived Measurements
Measure of density, speed, volume, etc.
(kg/m3) (m/s) (m3)
Thus these are combinations of SI units.

9. M x 10n Scientific Notation where is 1≤ M ≤ 10 and n is an integer
Physics is exciting because it deals with the very, very small to the very, very large.
Numbers can be written
M x 10n
where is 1≤ M ≤ 10
and n is an integer

10. Examples & Practice 5.) 560 000 000 m 6.) 0.000 003 5 m
Examples: 1.) g 2.) g 3.) 6.0x107 g 4.) 1.0x10-8 g 5.) 5.60x108 m 6.) 3.5x10-6 m 7.) m 8.) m
Answers:
1.) 8.1x105 g
2.) 6.43x10-4 g
3.) g
4.) g
5.) m
6.) m
7.) 9.24x10-3 m
8.) 8x105 m

11. Sometimes when dealing with the very, very small or very, very large, instead of using scientific notation, it is easier to use prefixes.
For example,
measuring the length of an ant,
the length of the school,
the diameter of the Earth and
the distance to the next closest star
are all very different sizes. We could use a meterstick for all but there would be a lot of zeros. . . So we use prefixes.

12. Larger & Smaller ones Factor Name Symbol 10-1 deci d 10-2 centi c 10-3
Factor
Name 
Symbol
10-1
deci d
10-2
centi c
10-3
milli m
10-6
micro
10-9
nano n
10-12
pico p
10-15
femto f
10-18
atto a
10-21
zepto z
10-24
yocto y
Factor
Name 
Symbol
1024
yotta Y
1021
zetta Z
1018
exa E
1015
peta P
1012
tera T
109
giga G
106
mega M
103
kilo k
102
hecto h
101
deka da
Ex. Nanotechnology
Kilobytes, megabytes, gigabytes, etc.

13. There are two basic ways to convert from one prefix to another.
1.) The “Down Right Easy Method” This is the moving the decimal method that you learned in middle school. 2.) The “Conversion Method” This is the multiplying by a conversion factor, you learned this in high school. Personally, I think you need both!

14. Down Right Easy Method
kilo- k 1000x hecto- h 100x decka- D 10x base (m, L, g) deci- d 1/10 or 0.1 centi- c 1/100 or 0.01 milli- m 1/1000 or Examples: 134 m = km hm = cm mm = Dm 15.7 Dm = dm
0.134
2 350
0.8542
1 570

15. Conversion Method
Convert 5021 cm to km. 5021cm 1m 1km = 5.021x10-2 km 100cm 1000m or km How many seconds in a leap year? 366 days 24 hours 60 min 60 sec 1 day 1 hour 1 min = 3.16 x 107 sec
The conversion factor!
The two numbers are equal to each other
So it is the same as multiplying by 1.

16. How many MHz are in 750 kHz. 750 kHz 1000 Hz 1x106 MHz 1 kHz 1 Hz = 0
How many MHz are in 750 kHz? 750 kHz 1000 Hz 1x106 MHz 1 kHz 1 Hz = 0.75 MHz Convert the speed 5.30 m/s to km/h m 1 km 60 s 60 min s 1000 m 1 min 1 hr = 19.1 km/h

17. Mathematics & Physics
Convert each of the following measurements to meters:
A.) 42.3 cm
B.) 21 km
C.) mm
D.) 6.2 pm
E.) 214 mm
F.) 57 nm
A.) m
B.) 2.1x104m
C.) 2.3x10-5m
D.) 6.2x10-12m
E.) 2.14x10-4m
F.) 5.7x10-8m

18. Rank the following mass measurements from least to greatest:
11.6 mg 1021 mg kg 0.31 mg
0.31 mg 1021 mg kg 11.6 mg

19. Significant Figures (Sig Figs) (SF)
All measured digits are significant.
Zeros may or may not be significant.
Sandwiched zeros ARE significant
Zeros actually measured ARE significant
Place holding zeros are NOT significant
Use scientific notation to indicate sig. figs.
MULTIPLICATION & DIVISION fewest sig. figs.
ADDITION & SUBTRACTION
fewest decimal places

20. State the number of significant figures in each of the following measurements:
A.) m B.) fm C.) m D.) mg E.) 2.40x106 kg F.) 6x108 kg G.) 4.07x1016 m
A.) 1 B.) 4 C.) 5 D.) 3 E.) 3 F.) 1 G.) 3

21. “EE “ = “EXP” = “times ten to the”
Calculators!
Calculators are ALWAYS allowed.
They are your friend, BUT
they are only as smart as the operator.
YOU must enter the numbers in the correct order of operation.
Use the Exponent key!!!!!!!!
“EE “ = “EXP” = “times ten to the”
P.S. The answer is ALWAYS NO, you may not use your cell phone/other electronic device calculator

22. Examples & Practice Add or subtract a indicated (in your calculator!).
A.) 6.12x109s
B.) 2.94x10-6m
C.) 1.250x10-4kg
D.) 7.50x107g
A.) 5.80x109s x108s B.) 4.87x10-6m – 1.93x10-6m C.) 3.14x10-5kg x10-5kg D.) 8.12x107g – 6.20x106g
We actually practiced 3 things here . . .
1.) scientific notation
2.) using our calculators and
3.) significant figures. 

23. Add or subtract as indicated.
E.) 16.2 m m m F.) m m m G.) cm2 – cm2 H.) kg – 12.0 kg
E.) 34.7 m F.) m G.) cm2 H.) 3.1 kg
In addition to the things we practiced on the last slide we are also practicing conversions! 

24. Multiply or divide as indicated.
I.) (6.2x1018 m)(4.7x10-10 m) J.) (5.6x10-7 m)/(2.8x10-12 s) K.) (8.1x10-4 km)(1.6x10-3 km) L.) (6.5x105 kg)/(3.4x103 m3)
I.) 2.9x109 m2 J.) 2.0x105 m/s K.) 1.3x10-6 km2 L.)1.9x102 kg/m3
In addition to the things we practiced on the last two slide we are also practicing SI units! 

25. Some of the strategies for studying the physical world are . . .
List all possible solutions
Look for patterns
Construct a table, graph, or figure
Make a model
Guess & Check
Work backwards
Make a drawing
Solve a simpler or similar problem

26. These organized strategies lead us to the Scientific Method . . .
Before Philosophy People sat around and theorized. After Scientific Method The theories are now tested!

27. Science and Religion (not vs. they are not competing)
Science is about cosmic order Religion is about cosmic purpose

28. Science is a way of knowing. Technology is a way of doing.
Science in general . . .
Science is a way of knowing.
Technology is a way of doing.
Ex. electricity – the science
light bulbs & computers technology

29. Some people feel that science and technology are bad and harmful ...
Make a distinction between the “thing” and the abuse of the “thing” Ex. Medicines – good Drug abuse – bad, the abuse of medicine

30. Hypothesis not supported
There is NO single “Scientific Method,” however all scientists study problems in an organized way.
State the problem
Gather information
Form a hypothesis
Test the hypothesis
Analyze data
Hypothesis not supported
Hypothesis supported
Draw Conclusions

31. Tools in our Physics Toolkit Problem Solving . . .
5 steps ALWAYS SHOW YOUR WORK!!!
Knowns
Unknowns
Equations (just variables)
Work-equation with numbers plugged in
Answer with units and correct sig-figs
(Gather information)
(State the problem)
(Form a hypothesis)
(Test the hypothesis)
Analyze data
Draw Conclusions

32. What are we trying to find?
Example Problem page 91
Knowns:
m = 1500 kg
a = m/s2
What is given in the problem?
What are we trying to find?
Unknown:
F = ?
Which equation has those variables in it?
Solve for the unknown variable:
Equation:
F = ma
Plug in the values and solve:
Work:
F = (1500 kg)(+3.00 m/s2)
State your answer with unit and correct sig figs.:
Answer:
F = 4500 N