Physics Chapter 1: The Science of Physics

 Physics Is Everywhere!  Motion  Heat  Sound  Light  Electricity

The Science of Physics  Scientific Method ObservationQuestionsHypothesis Experimentation Proven Results Theory Unexpected Results Revise Hypothesis Experimentation 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 (m 2 )  Volume – cubic meter (m 3 )  Density* – kilogram/cubic meter (kg/m 3 )  Pressure – Pascal kg/m*s 2 (Pa)  Energy – Joule kg*m 2 /s 2 (J)

The Science of Physics

 Greek Prefixes  Multipliers of SI Units  GigaG10 9  MegaM10 6  Kilok10 3  Centic10 -2  Millim10 -3  Micro   Nanon10 -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 -2 m = 6.65m  665km = 665x10 3 m = 6.65x10 5 m

The Science of Physics  Converting Unit Quantities  Examples (cont.):  112g = 1.12x10 2 g = 1.12x10 -1 kg (0.112kg)  200Gs = 200x10 9 s = 2x10 11 s  40ns = 40x10 -9 s = 4x10 -8 s

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  43  g = ______________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? AccuratePrecise

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?4  ?2  8.200m?4  600m?1  1.75m m = 4.19m  323.5m x 12.45m = m

The Science of Physics  Homework:  Pages 27 – 31  Problems  2  5  11b, c, e, g

The Science of Physics  Presenting Data  Tables  Graphs Letter Grade # of Students A3 B7 C10 D2 F1 Grade Distribution for Spring 2007

The Science of Physics  Graphs  Depending on Your Data, You Must Choose the Type of Graph that Best Presents Your Data  Bar  Line  Pie

The Science of Physics  Graphs  Variables  Independent Variable (IV)  Manipulated by the Experimenter  Represented on the “x” axis  “Control”  Dependant Variable (DV)  Variable(s) in the Experiment that are Results Dependant on the Independent Variable  Represented on the “y” axis  Experimental  Time Exception DV IV

The Science of Physics  Graphs  Slope

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

The Science of Physics  Correlation Does Not Imply Causation

The Science of Physics  Correlation Does Not Imply Causation

The Science of Physics  Correlation Does Not Imply Causation

The Science of Physics  Correlation Does Not Imply Causation

The Science of Physics  Correlation Does Not Imply Causation

The Science of Physics  Y Intercept  The “y” Value When the “x” Value is “0”

The Science of Physics  Problem (Sig Figs)  16.2m m m =

The Science of Physics  Solution (Sig Figs)  16.2m m m = 34.7m

The Science of Physics  Problem (Sig Figs)  5.006m m m =

The Science of Physics  Solution (Sig Figs)  5.006m m m = m

The Science of Physics  Problem (Sig Figs)  78.05cm 2 – cm 2 =

The Science of Physics  Solution (Sig Figs)  78.05cm 2 – cm 2 = 46.00cm 2

The Science of Physics  Problem  What is the mass of 30cm 3 of each substance?

The Science of Physics  Solution  What is the mass of 30cm 3 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? 34cm 3, 11cm 3, 7cm 3,

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)(m/s 2 )

The Science of Physics  Solution Force (N)(m/s 2 )

The Science of Physics  Problem  What is the relationship shown between force and acceleration? Force (N)(m/s 2 )

The Science of Physics  Solution  Linear Force (N)(m/s 2 )

The Science of Physics  Problem  What is an equation relating this force to acceleration relationship? Force (N)(m/s 2 )

The Science of Physics  Solution Force (N)(m/s 2 )

The Science of Physics  Problem  What are the units of the slope of the graph? Force (N)(m/s 2 )

The Science of Physics  Solution Force (N)(m/s2)

The Science of Physics  Trigonometry  Definitions  side opposite side adjacent hypotenuse

The Science of Physics  Trigonometry  Definitions  side opposite side adjacent hypotenuse

The Science of Physics  Trigonometry  To Find SidesTo Find Angles

The Science of Physics  Trigonometry  Problem:  Bowling for Faces  The rope is 225cm. What distance (o) is required horizontally to acquire a 40 0 angle? o 40 0

The Science of Physics  Trigonometry  Solution:  Bowling for Faces  The rope is 225cm = 2.25m (L). o 40 0 h

The Science of Physics  Trigonometry  Solution:  Bowling for Faces  The rope is 225cm = 2.25m (L)  r = 1.45m  What is the increase in the height of the ball? o 40 0 h a

The Science of Physics  Trigonometry  Solution:  Bowling for Faces  The rope is 225cm = 2.25m (L)  r = 1.45m  What is the increase in the height of the ball? o 40 0 h a

The Science of Physics  Problem: A speed of 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: km/hr = 515.2x10 3 m/hr = 5.15x10 5 m/hr = 5.15x10 5 m/3600s = 1.43x10 2 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  L?

The Science of Physics  Solution: 1.5L / 1x10 -3 = 1.5x10 3 mL 1.5L / 1x10 -6 = 1.5x10 6  L

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?

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? 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? 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? 100m 12.0m 

The Science of Physics  Homework:  Pages 27 – 31  Problems  20  30  38  41