Welcome to Physics!! Day One Agenda:  Who are we?  Formalities  Syllabus: Online!  Books, Reference Tables  Tissues = Gold  What is Physics?  Unit 1 !!!

Scientific Calculators ► Texas Instruments = Good ► Casio = Garbage MediocreBest!! TI-30XIIS Target Practice

Quiz! ► Doesn’t Count (except if not complete) ► Try ALL Questions ► Used as a status indicator

Topic Pre-I: Measurement and Mathematics  What do we use to measure Physics?  How are accuracy and precision different?  What is scientific notation?  How can quantities be represented on graphs? Essential Questions

I. Units A. “Comparison to a known standard” B. MOST numbers have a unit and they MUST be written (usually a symbol) C. The SI System 1. Used everywhere

2. Fundamental Units: Simplest Examples: Meters (m)Seconds (s) Examples: Meters (m)Seconds (s) 3. Derived Units: put two or more fundamental units together Example: Example: Force = = Newtons (N) kilogram meter second 2 kg m s 2 s 2 F =

4. Fundamental Prefixes: PRT’s Front Cover!

D. Addition and Subtraction require all quantities to have the same units Example: Example: 200km m = ? Should Be: 200 km + 34 km = ? 200 km + 34 km = ? or: 200,000 m + 34,000 m = ?

II. Measurements, Units, & Instruments LengthMassTimeForce Name of Instrument Ruler Triple Beam Balance Stopwatch/Clock Spring Scale (m) (kg) (s) (N)

Name of Instrument VolumeTemperature Graduated Cylinder Thermometer (L) (K) (°C)

Name of Instrument AnglesElectricityProtractor Voltmeter Ammeter (°) (V) or (A)

Journal #18/28/13 ► What is 6.37 x 10 5 m in standard form? ► What is in scientific notation? ► How many megameters are in 5,500,000 m? ► How many kilometers are in 5,500,000 m? ► Which of these is NOT a fundamental unit?  meters, Newtons, meters per second, kilograms

III. AKA: Sig Figs PRESERVE ACCURACY!! A. The Rules 1. All NON-Zero digits are significant 2. Zeros before a nonzero are NOT significant cm cm ONE significant digit 0.75 cm 0.75 cm TWO significant digits

3. Zeros between two nonzero digits ARE significant 25,001 Ω 25,001 Ω FIVE significant digits kg kg THREE significant digits 4. Zeros to the right of a nonzero digit ARE significant if followed by a decimal or are to the right of a decimal 30 sec 30 sec 40. sec 40. sec 10.0 sec 10.0 sec sec sec ONE TWO THREE FOUR

5. Correct number of Significant Digits is always shown automatically when scientific notation is used Example: 2.45 x 10 8 has 3 sig figs 6. Operations using sig figs One Rule: Final answers have the same number of significant digits as the LEAST sensitive measurement (lowest number of sig digs) One Rule: Final answers have the same number of significant digits as the LEAST sensitive measurement (lowest number of sig digs)

Add: 420 cm m 0.80 m Example

B. Estimating Orders of Magnitude 1. Always think in powers of 10  10 3 = = = = 0.01etc = = 0.01etc. 2. Examples: a pencil is closest to _____ kilograms a pencil is closest to _____ kilograms the distance from Arlington to Carrollton is closest to _____ kilometers the distance from Arlington to Carrollton is closest to _____ kilometers

Journal #28/29/13 ► What is 4.98 x 10 9 m in standard form? ► How many gigameters is the above distance? ► How many megameters is the above distance? ► How many kilometers is the above distance? ► How many significant figures are in each of the numbers below?  100,000,005 m8.621 x 10 3 V  s200 s ► Add: 2.3 km, 3500 m, and km With proper sig figs!!

IV. Precision vs. Accuracy A. Precise = measurements with great detail (More decimal places) B. Accurate = Acceptable, consistent measurements (close to the scientifically proven values)

A. Vectors are arrows that represent actual measurements to scale Example: Let 1 meter = 1 centimeter Example: Let 1 meter = 1 centimeter Therefore: 50 m would be a 50 cm arrow V. The number of a vector is its magnitude The number of a vector is its magnitude

B. Vectors have both magnitude and direction Examples: Examples:  velocity  force 22 m/s East 45 N at 30 o C. Scalars: values that only have magnitudes (a certain number of something) Examples: Examples:  time  mass 30 Seconds 100 Kilograms

D. Vector Combination 1. Can involve both addition and subtraction 2. Resultant: A combination of two or more vectors 3. Vectors are always combined tip to tail (start of one to end of other) + = Resultant

4. If vectors are acting in different directions, find the difference in magnitudes and combine tip to tail to find the direction  resultant points the same direction as the largest vector + = ? = Resultant

5. Vectors at angles to each other are still combined tip to tail!  angles of vectors must be preserved

 The resultant connects the beginning of the first vector to the end of the last vector

 Most cases only involve two vectors

 sometimes there can be multiple vectors involved, but the process stays the same! Resultant

 Graphical vector combination can be done using metric rulers and protractors!  Graphical vector combination can be done using metric rulers and protractors!

Journal #38/30/13 ► Find the hypoteneus in the following triangle! ► Then use “trig” to find the angle! 10m 18m

Journal #49/3/13 ► Find the hypotenuse and adjacent side in the following triangle if the angle θis 22.6° 5m ? ? θ

E. Breaking Down Vectors 1. It is MUCH easier to combine vectors using horizontal and vertical components 2.horizontal component = X component vertical component = Y component

3. X and Y components can be combined + = + = All X components are Horizontal All Y components are Vertical

4. Diagram of Vector C and Its X – Y Components Horizontal Component   Vertical Component  subscripts on the components differentiate them from the original vector C 

6. Horizontal and Vertical components make a right triangle so any side can be found cos θ = A/H Adjacent = A x Hypotenuse = A A x = A cosθ sin θ = O/H Opposite = A y Hypotenuse = A A y = A sinθ

7. Example : Ali drags a heavy box with a tensional force that acts up to the right at an angle of 40 degrees. What are the horizontal and vertical components of the force?

1. Used to express very large and very small quantities 2. General Form: A x 10 n A is a number between 1 and 10 A is a number between 1 and 10 n is a “power” equal the number of places to move the decimal point n is a “power” equal the number of places to move the decimal point  + for numbers greater than 1  - for numbers less than 1 VI. Scientific Notation

4. Multiplying and Dividing Sci. Notation Rules: Rules:  To multiply, add powers of ten (the n’s) and multiply the other numbers (the A’s)  To divide, subtract the powers of ten (the n’s) and divide the other numbers (the A’s) 3. Adding and Subtracting Sci. Notation  make the powers of ten (n’s) the same and then just add (the A’s) together

Examples:100 = 100,000 = =

Addition Example: 2.1 x 10 5 kg x 10 4 kg  Final Answer: 2.97 x 10 5 kg

Multiplication/Division Examples:  Multiply: (1.5 x 10 5 km) (2.8 x 10 3 km)  Divide: (1.5 x 10 5 km) (2.8 x 10 3 km)

VII. The Trig of Physics A. Right Triangles are used VERY OFTEN in Physics

B. Use the Pythagorean Theorem to solve for the length of a missing side Formula:

C. Angle Trig SOH CAH TOA Oscar Had A Heap Of Apples

 How on Earth do you remember all that??? It’s in the PRT’s!!! (page 5)

VIII. Graphs A. Format

B. Vocabulary Direct Interpolate Direct Interpolate Indirect Extrapolate Indirect Extrapolate Static Slope Static Slope Cyclic Cyclic Direct Squared Direct Squared Indirect Squared Indirect Squared

Frequency (Hz) Energy of a Photon (J) the slope of the graph is which means that the slope is proportional to

Elongation (m) Force of a Spring (N) the slope of the graph is which means that the slope is proportional to

the slope of the graph is which means that the slope is proportional to Force (N) Acceleration (m/s 2 )

Current (A) Potential Difference (V) ► Look up the symbols on the PRT’s for the variables shown on the graph below… then show the slope of the graph using the slope formula. ► Explain the significance of the slope of the graph ► State the relationship shown on the graph along with the type of relationship. Journal #X9/10/13