Transcript A Physics Toolkit

What do you think about when
You see the word PHYSICS?
Physics is a branch of knowledge
That involves the study of the
Physical world.
 Physics is Everywhere 
Name
Subjects
Examples
Mechanics
Motion
Falling objects
Thermodynamics
Heat & Temp
Melting
Vibrations &
Waves
Optics
Repetitive
motions
Light
springs, waves
Electromagnetism
Electricity
Circuits
Relativity
Moving at high
speeds
Particles
Nuclear energy
Quantum
Mirrors, lenses
Atoms and parts
In Physics we will ONLY use
The Metric System (or SI).
Base Quantity
Length
Mass
Time
Temperature
Electric
Current
Luminous
Intensity
Base Unit
Meter
Kilogram
Second
Kelvin
Ampere
Symbol
m
kg
s
K
A
Candela
cd
SI Prefixes
Prefix
Tera
Giga
Symbol
T
G
Scientific Notation
1012
109
Mega
Kilo
Base
M
k
106
103
1
Deci
Centi
Milli
d
c
m
10-1
10-2
10-3
Micro
Nano
Pico
Femto
µ
n
p
f
10-6
10-9
10-12
10-15
Significant Digits
The digit in a measurement that is certain
Plus the digit that is an estimate.
For example, 31.7 has 3 significant digits
When are digits significant
and when are they not?
Let’s read the rules and find out.
When a zero is not significant…
A zero that is simply a place keeper
Is not a significant digit, such as…
1040
31.7
This number has 3 sig. figs.
And this number has 2
3500
How do you know how many
there are?
The Atlantic-Pacific Rule!! 
Of course!
If you can remember where the
oceans are, you can remember this rule.
If a decimal point is present, count the
significant digits from the Pacific side,
that is, the left side.
If a decimal point is absent, count from
the Atlantic side, that is from the Right.
Now, you should start counting from the
1st non-zero digit that you find. All the
Digits from to the end are significant,
Including any zeros.
How many significant digits (sig. figs.)
Are there in these numbers?
0.0026701
5 sig. figs.
19.0550
6 sig. figs.
3500
2 sig. figs.
1809000
4 sig. figs.
Your book, and you should too,
Write many measurements with
Decimals, this way whole numbers
Stay meaningful.
100.
250.
Sig. Figs. In Calculations.
When an exact number appears in
A calculation, it does not affect the
Number of sig. figs. In the final answer.
In multiplication and division,
the measurement
With the smallest number of
sig. figs. Determines the number
of sig. figs. In the Answer.
In addition and subtraction, the number of
Sig. figs. Allowed depends on the
Number with the largest uncertainty.
3.05 X 2.10 X 0.75 = 4.80375 = 4.8
951.0 + 1407 + 23.911 + 158.18 = 2540
Practice these on your own…
12.7 km
3.0
= 4.2km
35.6 L + 2.4 L
4.803
= 7.91L
2.542 m X (16.408m – 3.88 m) = 31.85 m2
Scientific notation is a short hand way
Of writing really small or
Really big numbers!!
Such as …
227800000000 = 2.278 X 1011
Or…
0.000000000000000000000000000000911
Is the same as
9.11 X 10-31
Convert the following numbers to
Scientific notation…
a) 450000
b) 302000000
c) 0.00000045
a) 4.5 X 105
b) 3.02 X 108
c) 4.5 X 10-7
Every year in science you get
To hear about the scientific method.
This is because anytime you do an
Experiment, your results must
Be reproducible!
A Hypothesis is an educated guess.
Typically the order is question,
Hypothesis, experiment, measurements,
Calculations, then summarize.
In the end you might come up
With a new scientific law.
A scientific law is a rule of nature
That sums up related observations
To describe a pattern in nature.
You could also end up with a scientific
Theory.
A scientific theory is an explanation
Based on many observations
Supported by experimental results.
A measurement is a comparison
Between an unknown quantity
And a standard.
Your measurement is only as good
As the thing you measure with!
Precision describes the degree
of exactness of a measurement.
Accuracy describes how well the results
Of a measurement agree with the actual value.
There are basically 2 different and
Major ways to see data (measurements).
Graphs and Tables
We will use graphs almost all the time.
An independent variable is the
Factor that is changed
During the experiment
The dependant variable is the factor
That depends on the independent
Variable.
Plotting a line graph…
1.Identify the independent variable and
the dependant variable in your data.
The independent variable is plotted on
The horizontal axis and the dependant
Variable is plotted on the vertical axis.
2. Determine the range of the variables
To be plotted.
3. Decide whether the origin is a valid point.
4. Spread the data out as much as possible.
5. Number and label the axis.
6. Plot the points on the graph.
7. Draw a best fit line.
8. Give the graph a title that
Represents what is being shown.
Linear relationships have a straight line
On a graph, and can be defined by
The slope of that line.
y = mx + b
m = Δy / Δx
Nonlinear relationships have
Different shapes. (like a parabola)