Transcript AP Physics B

Physics
Chapter 1:
The Science of Physics
The Science of Physics
Physics Is Everywhere!
Motion
Heat
Sound
Light
Electricity
The Science of Physics
Scientific Method
Observation
Questions
Unexpected Results
Hypothesis
Experimentation
Proven Results
Revise Hypothesis
Experimentation
Theory
Prediction
The Science of Physics
Scientific Model
A Representation of an Object or Event
Explains Basic Features of Complex Systems
Allows Scientists to Test Hypotheses on a
Realistic Scale
Humans
Meteor Impact
Gravity in the Universe
The Science of Physics
Branches of Physics
Mechanics
Wave Phenomenon
Optics
Thermodynamics
Electromagnetism
Relativity
Quantum Mechanics
The Science of Physics
Le Système International d’Unités
SI
Units Universally Used by Scientists
The Science of Physics
SI Units (Base)
Length – meter (m)
Mass – kilogram (kg)
Time – second (s)
Temperature – Kelvin (K)
Amount – mole (mol)
The Science of Physics
SI Units (Derived)
Area – square meter (m2)
Volume – cubic meter (m3)
Density* – kilogram/cubic meter (kg/m3)
Pressure – Pascal kg/m*s2 (Pa)
Energy – Joule kg*m2/s2 (J)
The Science of Physics
The Science of Physics
Greek Prefixes
Multipliers of SI Units
Giga
Mega
Kilo
Centi
Milli
Micro
Nano
G
M
k
c
m
m
n
109
106
103
10-2
10-3
10-6
10-9
The Science of Physics
Converting Unit Quantities
When converting a smaller unit to a
larger unit move the decimal left and add
to exponent
Scientific Notation Rules Apply
Examples:
665cm = 665x10-2m = 6.65m
665km = 665x103m = 6.65x105m
The Science of Physics
Converting Unit Quantities
Examples (cont.):
112g = 1.12x102g = 1.12x10-1kg (0.112kg)
200Gs = 200x109s = 2x1011s
40ns = 40x10-9s = 4x10-8s
The Science of Physics
Converting Unit Quantities
Examples (cont.):
12km = _____________m
225mm = ____________m
34cm = ______________m
650nm = _____________m
The Science of Physics
Converting Unit Quantities
Examples (cont.):
180g = _____________kg
125mg = ____________kg
43mg = ______________kg
The Science of Physics
Converting Unit Quantities
Examples (cont.):
450ns = _____________s
22min = ____________s
4hrs 12min = ______________s
The Science of Physics
Measurement
Precision
Your Ability to Reproduce Measurements
Accuracy
How Close is Your Measurement to the
Actual Measurement?
Precise
Accurate
The Science of Physics
Measurement Techniques
Use the Best Measuring Device for the Job
Use the Measuring Device Correctly
Avoid Parallax
The Science of Physics
Measurement
Significant Figures
Your Final Answer Cannot be More
Accurate than Your Least Accurate Entry.
In Scientific Notation All Digits are
Significant!
The Science of Physics
Measurement
Significant Figures (Rules)
Zeros between other Nonzero digits ARE
Significant
Zeros in Front of Nonzero digits ARE NOT
Significant
Zeros at the End of a Number, Right of the
Decimal ARE Significant
Zeros at the End of a Number, Left of the
Decimal ARE NOT Significant
The Science of Physics
Measurement
Significant Figures
1.024?
0.0039?
8.200m?
600m?
1.75m + 2.435m =
323.5m x 12.45m =
4
2
4
1
4.19m
4027.6m
The Science of Physics
Homework:
Pages 27 – 31
Problems
2
5
11b, c, e, g
The Science of Physics
Presenting Data
Tables
Letter Grade
# of Students
A
3
B
7
C
10
D
2
F
1
Grade Distribution for Spring 2007
Graphs
Grade Distribution for Spring 2007
Grade Distribution for Spring 2007
12
1, 4%
2, 9%
10
3, 13%
A
# of Students
8
B
6
C
7, 30%
4
D
10, 44%
2
F
0
A
B
C
Letter Grade
D
F
The Science of Physics
Graphs
Depending on Your Data, You Must Choose the
Type of Graph that Best Presents Your Data
Bar
Line
Pie
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Graphs
Variables
DV
Independent Variable (IV)
Manipulated by the Experimenter
Represented on the “x” axis
“Control”
IV
Dependant Variable (DV)
Variable(s) in the Experiment that are Results Dependant on
the Independent Variable
Represented on the “y” axis
Experimental
Time Exception
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Graphs
Slope
12
10
# of Students
y
m
x
Grade Distribution for Spring 2007
C
8
B
6
4
A
2
D
F
0
0
1
2
3
Letter Grade
4
5
6
The Science of Physics
Graphs
Slope Relationships
Directly proportional
x = y
Inversely
Proportional
Product of the two
Variables is Constant
y = 1/x
hyperbola
The Science of Physics
Linear Relationships
Directly Proportional
As IV Increases, DV Increases
As IV Decreases, DV Decreases
The Science of Physics
Non-Linear
Relationships
Parabola
DV Dependant on Square
of IV
Hyperbola
Inverse Relationship
IV Increases, DV
Decreases
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Correlation Does Not Imply Causation
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Correlation Does Not Imply Causation
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Correlation Does Not Imply Causation
The Science of Physics
Correlation Does Not Imply Causation
The Science of Physics
Correlation Does Not Imply Causation
Average Global Temperature vs. Number of Pirates
Global Average Temperature oC
Number of Pirates (Approximate)
40000
35000
15.5
30000
15
25000
14.5
20000
15000
14
10000
13.5
5000
13
0
1820
1860
1880
1920
YEAR
1940
1980
2000
APPROXIMATE NUMBER OF PIRATES
AVERAGE GLOBAL TEMPERATURE IN DEGREES CELSIUS
16
The Science of Physics
Y Intercept
The “y” Value When the “x” Value is “0”
The Science of Physics
Problem (Sig Figs)
16.2m + 5.008m + 13.48m =
The Science of Physics
Solution (Sig Figs)
16.2m + 5.008m + 13.48m = 34.7m
The Science of Physics
Problem (Sig Figs)
5.006m + 12.0077m + 8.0084m =
The Science of Physics
Solution (Sig Figs)
5.006m + 12.0077m + 8.0084m = 25.022m
The Science of Physics
Problem (Sig Figs)
78.05cm2 – 32.046cm2 =
The Science of Physics
Solution (Sig Figs)
78.05cm2 – 32.046cm2 = 46.00cm2
The Science of Physics
Problem
What is the mass of 30cm3 of each substance?
The Science of Physics
Solution
What is the mass of 30cm3 of each substance?
80g, 260g, 420g
The Science of Physics
Problem
What are the volumes of 100g of each
substance?
The Science of Physics
Solution
What are the volumes of 100g of each
substance?
34cm3, 11cm3, 7cm3,
The Science of Physics
Problem
What is the meaning of the steepness of the lines
of the graph?
The Science of Physics
Solution
The steepness represents the increased mass of
each additional cubic centimeter of the
substance.
The Science of Physics
Problem
A physics student placed a 1.0-kg mass on a horizontal
table that was nearly frictionless. The student then
applied various horizontal forces to the mass and
measured the acceleration for each force applied. The
results of the experiment are shown in this table. Plot
the values and draw the best fit curve.
Force (N)
5.0
10.0
15.0
20.0
25.0
30.0
(m/s2)
4.9
9.8
15.2
20.1
25.0
29.9
The Science of Physics
Solution
Acceleration Relative to Force Applied
35
30
FORCE (N)
25
20
15
10
5
0
5
10
15
20
ACCELERATION (M/S2)
25
30
Force (N)
5.0
10.0
15.0
20.0
25.0
30.0
(m/s2)
4.9
9.8
15.2
20.1
25.0
29.9
The Science of Physics
Problem
What is the relationship shown between force and
acceleration?
Acceleration Relative to Force Applied
35
30
FORCE (N)
25
20
15
10
5
0
5
10
15
20
ACCELERATION (M/S2)
25
30
Force (N)
5.0
10.0
15.0
20.0
25.0
30.0
(m/s2)
4.9
9.8
15.2
20.1
25.0
29.9
The Science of Physics
Solution
Linear
Acceleration Relative to Force Applied
35
30
FORCE (N)
25
20
15
10
5
0
5
10
15
20
ACCELERATION (M/S2)
25
30
Force (N)
5.0
10.0
15.0
20.0
25.0
30.0
(m/s2)
4.9
9.8
15.2
20.1
25.0
29.9
The Science of Physics
Problem
What is an equation relating this force to acceleration
relationship?
Acceleration Relative to Force Applied
35
30
FORCE (N)
25
20
15
10
5
0
5
10
15
20
ACCELERATION (M/S2)
25
30
Force (N)
5.0
10.0
15.0
20.0
25.0
30.0
(m/s2)
4.9
9.8
15.2
20.1
25.0
29.9
The Science of Physics
Solution
Force
slope(m) 
Acceleration
Acceleration Relative to Force Applied
35
30
FORCE (N)
25
20
15
10
5
0
5
10
15
20
ACCELERATION (M/S2)
25
30
Force (N)
5.0
10.0
15.0
20.0
25.0
30.0
(m/s2)
4.9
9.8
15.2
20.1
25.0
29.9
The Science of Physics
Problem
What are the units of the slope of the graph?
Acceleration Relative to Force Applied
35
30
FORCE (N)
25
20
15
10
5
0
5
10
15
20
ACCELERATION (M/S2)
25
30
Force (N)
5.0
10.0
15.0
20.0
25.0
30.0
(m/s2)
4.9
9.8
15.2
20.1
25.0
29.9
The Science of Physics
Solution
N
2
(m / s )
Acceleration Relative to Force Applied
35
30
FORCE (N)
25
20
15
10
5
0
5
10
15
20
ACCELERATION (M/S2)
25
30
Force (N)
5.0
10.0
15.0
20.0
25.0
30.0
(m/s2)
4.9
9.8
15.2
20.1
25.0
29.9
The Science of Physics
Trigonometry
opp
sin  
hyp
Definitions
hypotenuse
side opposite
adj
cos  
hyp

side adjacent
opp
tan  
adj
The Science of Physics
Trigonometry
  sin
Definitions
1

hypotenuse
side adjacent
side opposite
opp
hyp
adj
  cos
hyp
1
opp
  tan
adj
1
The Science of Physics
Trigonometry
To Find Sides
To Find Angles
opp
sin  
hyp
  sin
adj
cos  
hyp
adj
  cos
hyp
opp
tan  
adj
opp
  tan
adj
1
opp
hyp
1
1
The Science of Physics
Trigonometry
Problem:
400
Bowling for Faces
The rope is 225cm. What
distance (o) is required
horizontally to acquire a 400
angle?
o
The Science of Physics
Trigonometry
400
Solution:
h
Bowling for Faces
The rope is 225cm = 2.25m (L).
o
opp
sin  
hyp
opp
sin 40 
2.25m
0
opp  (sin 40)(2.25m)  1.45m
The Science of Physics
Trigonometry
400
Solution:
h
Bowling for Faces
a
The rope is 225cm = 2.25m (L)
r = 1.45m
What is the increase in the height
of the ball?
a2  b2  c2
c b  a
2
2
2.25  1.45  2.96
2
2
2
2
o
2.25  1.45  a
2
a  1.72m
2
2
The Science of Physics
Trigonometry
400
Solution:
h
Bowling for Faces
The rope is 225cm = 2.25m (L)
r = 1.45m
What is the increase in the
height of the ball?
a  1.72m
a
o
2.25m 1.72m  0.53m
The Science of Physics
Problem: A speed of 515.2 km/hr is the
highest recorded train speed on any national
rail system. Express this speed in meters per
second.
The Science of Physics
Solution:
515.2 km/hr = 515.2x103m/hr
= 5.15x105m/hr = 5.15x105m/3600s =
1.43x102 m/s = 143 m/s
The Science of Physics
Problem: A magnum of wine contains 1.5L.
How many mL does it contain?
How many mL?
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Solution:
1.5L / 1x10-3 = 1.5x103 mL
1.5L / 1x10-6 = 1.5x106 mL
The Science of Physics
Problem:
A hill that has a 12% grade is one that rises
12.0m for every 100m of distance. What is the
angle of the hill to horizontal?
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Solution:
A hill that has a 12% grade is one that rises
12.0m for every 100m of distance. What is the
angle of the hill to horizontal?
100m
12.0m

The Science of Physics
Solution:
A hill that has a 12% grade is one that rises
12.0m for every 100m of distance. What is the
angle of the hill to horizontal?
Θ = 𝑠𝑖𝑛
−1
𝑜𝑝𝑝
ℎ𝑦𝑝
100m
12.0m

The Science of Physics
Solution:
A hill that has a 12% grade is one that rises
12.0m for every 100m of distance. What is the
angle of the hill to horizontal?
Θ=
−1 12.0𝑚
𝑠𝑖𝑛
100𝑚
= 6.89o = 7o
100m
12.0m

The Science of Physics
Homework:
Pages 27 – 31
Problems
20
30
38
41