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Introduction to Physics: Course Structure and Objectives

This physics course provides an introduction to the principles and problems of classical mechanics. The course covers topics such as motion, energy, and vibrations, and aims to develop problem-solving skills and an understanding of the physical world. Lectures, assignments, and labs are included in the course curriculum.

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Introduction to Physics: Course Structure and Objectives

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  1. Physics 518 Agenda for Today • Course Introduction • General Announcements • Structure of the course • Scope of the course • Begin chapter 1 Course Homepage: http://physicsgbhs.weebly.com/

  2. 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

  3. 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

  4. Act Lecture • Three main components: • Discussion class material • Selected topics from text • Demonstrations of physical phenomenon • Physics is an experimental science Example: Egg Roll Today • Interactive exercise with conceptual “Active Learning” problems • Critical thinking and problem solving (Almost no memorization required)

  5. 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

  6. 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

  7. This Week • Position and Time (Chapter 1) • What is Physics • Scientific Method • Vectors • Scientific Notation • Systems of units • Dimensional Analysis • Significant digits

  8. Physics can also be described as the science of motion. What is Physics…..

  9. The Methods of Science

  10. What is Science? 1.  studies the natural world 2.  discovers knowledge 3.  discovers nature's "rules" about how things work 4.  only deals with natural phenomena and natural causes               *excludes supernatural

  11. Branches of Science 1.  Life science  (biology, microbiology, botany, evolution) - deals with living things 2.  Earth science (geology, meteorology) - earth, space, rocks, volcanoes, weather 3.  Physical science  (chemistry, physics) - matter, energy, gravity, light, sound

  12. 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

  13. 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

  14. 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

  15. Scientific Method

  16. Hypothesis • A possible explanation or solution to the problem (educated guess) • A hypothesis can be tested by – Making observations – conducting experiments, – taking measurements • The experiments and results must be reproducible; that is, other scientists must be able to recreate the experiment and obtain similar data.

  17. Scientific Theory • Scientific theory is – Based on numerous observations and supported by experimental results – A specific, testable statement about how things happen. – A conclusion that has held up over time and is accepted by most. (Theory of PlateTectonics) – is the best available explanation of why things work as they do. • It may be revised or discarded over time.

  18. Scientific Theory • Most people use the word THEORY to mean uncertainty, guesswork, or a rough idea – “oh…it is just a theory” …??????? • In science, a THEORY has a more specific meaning… – explains facts or phenomena that have been shown to be true by repeated independent tests and experiments.

  19. Scientific Law • a rule of nature that sums up related observations to describe a pattern in nature. • does not explain WHY these phenomena happen, it simply describes them

  20. A THEORY is an explanation of why something happens.  It comes from many observations and experiments.  It can be changed with new data. Examples:  Germ Theory                  Theory of Evolution A LAW tells you what happens, like a rule of nature.   Examples:  Law of Gravity                  Law of Thermodynamics

  21. Modeling Scientists sometimes use models to help visualize phenomenon.  The globe is a model you are familiar with. Name some other models.....

  22. 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?

  23. 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)

  24. Metric System • Fundamental or Base Unit: – a standard; a specific quantity – only seven (7) needed to describe all of nature

  25. Metric System

  26. 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.

  27. The Prefixes Most Commonly Used

  28. 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:

  29. 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:

  30. 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)

  31. 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

  32. Scientific Notation • Mass of Earth 6,000,000,000,000,000,000,000,000 kg = ? • Mass of an electron 0.000,000,000,000,000,000,000,000,000,000,911 kg = ? • Format: M x 10n where1 M < 10

  33. 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

  34. 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

  35. 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

  36. 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

  37. 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.

  38. 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

  39. 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

  40. 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

  41. 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

  42. 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

  43. Other Math Stuff

  44. 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

  45. Math in Physics:

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