Créer une présentation
Télécharger la présentation

Télécharger la présentation
## AP Physics 1

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**AP Physics 1**Agenda for Today • Course Introduction • General Announcements • Structure of the course • Scope of the course • Begin chapter 1 Course Homepage: http://physicsgbhs.weebly.com/**General Announcements**• Assignments: • Text: Glencoe Science: Physics Principles and Problems • Reading Assignment: Chapters 1 • Homework will do as Indicated on the Website and on the Board each day. • Lectures: (the PowerPoint component) will be posted at the course website • Videos:Selected YouTube videos will be availaible on line to help with learning the topcis**Grading**• Several components: • Lecture: Occasional reading quizzes • Homeworkand Classwork (15%) • Exams: 40 % Tests 30% Quizzes • Class time: • Review homework, at most one day per week • Cooperative learning exercises • Labs: (15%) • Mostly worksheets**Act**Lecture • Three main components: • Discussion class material • Selected topics from text • Demonstrations of physical phenomenon • Physics is an experimental science • Interactive exercise with conceptual “Active Learning” problems • Critical thinking and problem solving (Almost no memorization required)**Course Objectives**• To begin to understand basic principles (e.g. Newton's Laws) and their consequences (e.g. conservation of momentum, etc.) • To solve problems using both quantitative and qualitative applications of these physical principles • To develop an intuition of the physical world**Scope of Physics 518**• Classical Mechanics: • Mechanics: How and why things work. Motion (dynamics), balance (statics), energy, vibrations, some thermodynamics Classical: • Not too fast (v << c), c ≡ speed of light • Not too small (d >> atom), atoms 10-9 m • Most everyday situations can be described in these terms. • Path of baseball (or a ping pong ball) • Path of rubber ball bouncing against a wall • Vibrations of an elastic string (Vibration Demo) (These reflect Newton’s Laws and forces) • Properties of matter; a roll of the dice (Thermodynamics)**This Week**• Position and Time (Chapter 1) • What is Physics • Scientific Method • Vectors • Scientific Notation • Systems of units • Dimensional Analysis • Significant digits**Physics can also be described as the science of motion.**What is Physics…..**Lab Scientific Method**A step by step process where a scientist investigates a question by observing and performing experiments. Step 1 - State the problem or pose a question Step 2 - Gather information (has someone already investigated this?) Step 3 - Form a hypothesis -- a possible explanation or answer**Step 4 - Test the hypothesis with an experiment**Experiments have 2 variables Independent variable - what you change Responding variable (dependent) - what you measure If you want to test the affect of fertilizer, you would add fertilizer to a plant (independent variable) and measure how the plant grows (responding variable) A control is something you do nothing to, used to compare your results you will also have a plant that receives no fertilizer**Step 5 - Conclusion**Organize data into charts or graphs that can be read by others Step 6 - Draw Conclusions Determine if hypothesis is supported or rejected If hypothesis is not supported - modify hypothesis If hypothesis is supported - repeat experiment**Quick Review**• Experiment: an organized procedure for testing a hypothesis...typically has a control and independent and dependent variables. • Control: a standard for comparison • Independent variable: the factor (or variable) that is changed by the experimenter • Dependent variable: the factor (or variable) that responds to change in the independent variable?**Metric System**• Created by French scientists in 1798 – International System of Units (SI) – Units of different size related by powers of 10 • In USA, controlled by NIST (National Institute of Standards and Technology www.nist.gov)**Metric System**• Fundamental or Base Unit: – a standard; a specific quantity – only seven (7) needed to describe all of nature**Metric System**• To convert between SI units, multiply or divide by the appropriate power of 10. • Prefixes are used to change SI units by powers of 10, as shown in the table below.**Conversion Between Units**• A conversion factor is a multiplier equal to 1. For example, because 1 kg = 1000 g, you can construct the following conversion factors:**Conversion Between Units**• Choose a conversion factor that will make the units cancel, leaving the answer in the correct units. • For example, to convert 1.34 kg of iron ore to grams, do as shown below:**Conversion Between Units**• How many megahertz is 750 kilohertz? • Convert 5021 centimeters to kilometers. • How many seconds in a year? • Convert the speed 5.30 m/s to km/h (conversion miles to km is (1 Mile = 1.609344 km)**Scientific Notation**• Physicists like to measure the very big, the very small and everything in between. • Earth is about 149,000,000,000meters from the Sun. • Scientific notation expresses a quantity as a numbertimes a power of 10. 1.49×1011 meters = 14.9×1010 meters = .149×1012 meters …. which is correct? • Proper format: M x 10nwhere1 M < 10**Standard Scientific Notation:**A. Moving the decimal point to left exponent is ___________ number is _____ 1 5 positive 616000 = 6.16 x 10 left Shift ______ to here by ___ places > implied ________ decimal pt. 5 B. Moving the decimal point to right exponent is ___________ number is _____ 1 -3 0.0070 = 7.0 x 10 negative right Shift ______ to here by ___ places < 3**Ex: Convert to standard scientific notation**4.3 x 104 2.90 x 10-2 2.012 x 103 5 x 10-1 8 x 101 8.0 x 101**Measurements**• We measure things to know something about them; to describe, to understand • Measurements must be accurate and mean the same to all • include 3 pieces of information – magnitude (how much) – units – uncertainty**Measurements**• measurements are not numbers – numbers are obtained by counting or by definition; measurements are obtained by comparing an object with a standard "unit" – numbers are exact; measurements are inexact –mathematics is based on numbers; science is based on measurement**Measurement**• Significant digits (sig figs) • Include all the numbers that can be read directly from the instrument scale plus one doubtful or estimated number. • Reflect the precision of the measurement. • Significant digits are considered only when calculating with measurements. • There is NO uncertainty with counting or exact conversions.**Figures (numbers) are significant if they are:**• ________________ numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9 • any zeros that are: a. between any _________________ numbers: 509; or b. to the ___________ of a non-zero number AND to the ___________ of the decimal point: 0.00790; or c. between a non-zero number and the __________ _________ : 10. non-zero significant right right decimal point Ex: 5 2 4 3 1 1 2 2**6**1 2 4 3 5 Ex 1: Measure the length of a box: L 4.7 cm = 4.7 ± 0.1 cm L = last digit is _____________ estimated**6**1 2 4 3 5 Ex 2: Use a “better” ruler: L 0.01 cm = 4.67 ± L = 4.67 cm last digit is ______________ estimated**B. Sig. figs. when multiplying or dividing:**answer has the _________ number of sig. figs., in this case: ____ 3 ____ sig. figs. lower 3.73 x 5.7 = 21 2 ____ sig. figs. 2 C. Sig. figs. when adding or subtracting: 3 18.541 +106.6 125.1 • ___ decimal places • ___ decimal places 1 lower answer has the _________ number of ___________________ , in this case: ____ decimal places 1**Measurement**• Precision: –Degree of exactness –Reflects the ability to measure something – Limited by the smallest division on the measurement scale (least count) – Precision of a measurement is generally given as ± 0.1 the smallest division of the instrument • Accuracy: – closeness to a standard**Dy**VI. Slope = m = ________ Dx Steps: 1. Draw a best fit line using a __________ • Use two points on the line to calculate m: Steps: 1. Draw a best fit line using a __________ • Use two points on the line to calculate m: (x2, y2) = ( , ) ruler 8 32 40 30 y2 – y1 m = Dy = Dx = ________ = x2 – x1 20 32 - 5 8 - 1 10 (x1, y1) = ( , ) 1 5 3.9 0 0 6 8 2 4**Ball Bounce Lab**TPFT 3.2 Combined with: Graph Analysis TPFT 3.3 Techniques of Graphing TPFT 3.4