Welcome to our Physics Class!
• My name is Mr. Austin
• As you come in please do the following:
– write a word on the white board you
associate with Physics
– Pick up a copy of the syllabus located on the
front table
– Pick up, and complete, the “student
information sheet” located on the front table
– Pick up, and complete, the math practice
sheet from the front table.
Units
and
Measurement
Physics
Mr. Austin
International Space Station
http://apod.nasa.gov/apod/image/0706/iss_sts117_big.jpg
What is Physics?
• The study of the interaction between
energy and matter
• The study of:
– Motion
– Heat
– Light
– Energy
– Much More!
Math and Units
• Math- the language of Physics
• SI Units – International System
– MKS
• Meter m
• Mass kg
• Time s
• National Bureau of Standards
• Prefixes are used to simplify
SI Unit Prefixes - Part I
Name
Symbol
Factor
tera-
T
1012
giga-
G
109
mega-
M
106
kilo-
k
hecto-
h
deka-
da
SI Unit Prefixes- Part II
Name
Symbol
Factor
deci-
d
centi-
c
milli-
m
micro-
μ
10-6
nano-
n
10-9
pico-
p
10-12
femto-
f
10-15
SI Unit Prefixes for Length
Name
gigameter
megameter
kilometer
decimeter
centimeter
millimeter
micrometer
nanometer
picometer
Symbol
Gm
Mm
km
dm
cm
mm
μm
nm
pm
109
106
103
10-1
10-2
10-3
10-6
10-9
10-12
The Seven Base SI Units
Quantity
Unit
Symbol
Length
meter
m
Mass
kilogram
kg
Temperature
kelvin
K
Time
second
s
Amount of
mole
Substance
Luminous Intensity candela
mol
Electric Current
a
ampere
cd
Derived SI Units (examples)
Quantity
unit
Symbol
Volume
cubic meter
m3
Density
Speed
kilograms per
kg/m3
cubic meter
meter per second m/s
Newton
kg m/ s2
N
Energy
Joule (kg m2/s2)
J
Pressure
Pascal (kg/(ms2)
Pa
United States Customary Units
US Customary
SI Equivalent
1 Foot
1 yard
1 mile
1 Pound
1 Pound
1 mile per hour
.3048 meters
.9144 meters
1.609344 kilometers
4.44822 Newtons
.45359237 kilograms
.44704 meters per
second
Scientific Notation
Mx
n
10
• M is the coefficient 1<M<10
• 10 is the base
• n is the exponent or power of 10
Other Examples:
• 5450000 =
Numbers less than 1 will have a
negative exponent.
A millionth of a second is:
0.000001 s
Write in Scientific Notation
• 3250 =
• .000435 =
• 425620000 =
Factor-Label Method of Unit
Conversion
• Example: Convert 5km to m:
• Multiply the original measurement by a
conversion factor.
– A _________of the new unit to the old unit
NEW UNIT
85km x 1,000m
1km
OLD UNIT
=
85,000m
Factor-Label Method of Unit
Conversion: Example
• Example: Convert 789m to km:
Convert 75.00 km/h to m/s
Scientific Notation Math Review
Area
• A measure of the two dimensional space
occupied by an object
• Derived SI unit of _________
• It is always the product of two dimensions
of an object
Surface Area
• The two dimensional area that surrounds a
three dimensional object.
• Derived SI unit of ________
• It is always the product of two dimensions
of an object
Volume
• The 3 dimensional space taken up by an
object.
• Derived SI unit of _______
• It is always the product of three
dimensions of an object
Density
• The ratio of an objects ________(in
Kilograms) to its _________(in meters
cubed)
– Derived unit of ________
• We will look at objects with uniform
density.
– The ratio is the __________no matter how
small or large the object’s volume is made.
Density (kg/m3)
Material
Paper
1000
Steel
19300
Neutron Star
• Accuracy - a measure of how
________a measurement is to
the true value of the quantity
being measured.
Example: Accuracy
• Who is more accurate when
measuring a book that has a true
length of 17.0cm?
Susan:
17.0cm, 16.0cm, 18.0cm, 15.0cm
Amy:
15.5cm, 15.0cm, 15.2cm, 15.3cm
• Precision – a measure of how
close a series of measurements
are to _____________. A
measure of how exact a
measurement is.
Example: Precision
Who is more precise when measuring
the same 17.0cm book?
Susan:
17.0cm, 16.0cm, 18.0cm, 15.0cm
Amy:
15.5cm, 15.0cm, 15.2cm, 15.3cm
Example: Evaluate whether the
following are precise, accurate or
both.
Practice!
• Please complete the following problems in
class. What you do not finish will be
homework to be turned in tomorrow.
• Pg. 8-11 # 1, 5, 7, 20, 34 (house-ception!)
3 Kinds of Variables
• Independent Variable – something
that is changed by the scientist
– What is tested
– What is manipulated
3 Kinds of Variables
• Dependent Variable – something that
might be affected by the change in
the independent variable
– What is observed
– What is measured
– The data collected during the
investigation
3 Kinds of Variables
• Controlled Variable – a variable that
is not changed
– Also called constants
– Allow for a “fair test”
For Example:
Students of different ages
were given the same jigsaw
puzzle to put together.
They were timed to see how
long it took to finish the
puzzle.
Identify the variables in this
investigation.
What was the independent
variable?
• Ages of the students
–Different ages were tested by
the scientist
What was the dependent variable?
• The time it to put the puzzle
together
–The time was observed and
measured by the scientist
What was a controlled variable?
• Same puzzle
–All of the participants were
tested with the same puzzle.
–It would not have been a fair
test if some had an easy 30
piece puzzle and some had a
harder 500 piece puzzle.
Graphing