1 / 47

Intro to Physics

Intro to Physics. (Chapter 1). PHYSICS. is an attempt to describe in a fundamental way, the nature and behavior of the world around us. is about the nature of basic things such as motion, forces, energy, matter, heat, sound, light, and the inside of atoms. PHYSICS.

laner
Télécharger la présentation

Intro to Physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Intro to Physics (Chapter 1)

  2. PHYSICS is an attempt to describe in a fundamental way, the nature and behavior of the world around us. is about the nature of basic things such as motion, forces, energy, matter, heat, sound, light, and the inside of atoms.

  3. PHYSICS Often uses mathematics as its language. Is inherently a science of measurement. Did you know Newton invented calculus to explain some areas of physics?

  4. AREAS OF PHYSICS Mechanics: is concerned with the effects of forces on material objects. Thermodynamics: deals with heat, temperature, and the behavior of a large number of particles.

  5. AREAS OF PHYSICS Electromagnetism: deals with charges, currents, and electromagnetic fields. Relativity: is the theory that describes particles moving at any speed, and connects space and time.

  6. AREAS OF PHYSICS Quantum Physics: deals with the behavior of particles moving at the submicroscopic level as well as the microscopic world. Vibrations and Wave Phenomena: deals with specific types of repetitive motion.

  7. SCIENTIFIC METHOD is the series of steps used to solve a problem. It is the systematic study of a question or problem.

  8. STEPS OF THE SCIENTIFIC METHOD • Recognize problem • Gather information • Make hypothesis • Perform experiment • Analyze data • Draw conclusion

  9. PROBLEM A problem is a situation in which something appears to be missing. Recognize the problem and do background research in order to learn about the problem.

  10. HYPOTHESIS A hypothesis is an educated guess or possible explanation given as a solution to the problem. It must be a testable explanation for observations. It is often stated in the form of a question.

  11. EXPERIMENT An experiment is a controlled test of a hypothesis. A variable is something that causes a change in an experiment. A good experiment will test only one variable at a time, all other conditions must be held constant. These conditions are called constants.

  12. INDEPENDENT VARIABLE • Is the variable which in your control. • It is the variable which is plotted on the x-axis. X-axis

  13. DEPENDENT VARIABLE • Is the variable which is dependent on the independent variable. • It is what you measure. • It is always plotted on the y-axis. Y-axis

  14. An experiment must also have a control . A control is a standard for comparing results, or a group that does not receive the treatment. In an experiment data must be recorded. Data are the recorded facts of the experiment such as measurements or observations.

  15. Draw conclusions based on the data collected. The conclusion of an experiment must answer the question posed by the hypothesis.

  16. When a hypothesis has been tested and supported many times a theory is formulated. A theory is the best explanation science has to offer about a problem. As new information is collected, a theory may need to be revised or discarded and replaced with another theory.

  17. A scientific law is a rule of nature that sums up related observations and experimental results to describe a pattern in nature. When scientific discoveries are used to solve everyday problems or enhance the quality of life it is called technology.

  18. STANDARD Standard is an exact quantity that people agree to use for comparison. When all measurements are made using the same standard, the measurements can be compared to each other.

  19. MEASUREMENT SYSTEMS All scientific measurements are made using the International System of Units or SI system. Most SI units are based on the metric system.

  20. Every type of quantity measured in SI has a base unit and a symbol for that unit. There are seven base units and all other units can be derived from these seven base units.

  21. UNITSYMBOL meter m kilogram kg second s ampere A Kelvin K QUANITY MEASURED • Length • Mass • Time • Electric Current • Temperature

  22. QUANITY MEASURED • Amount of a Substance • Intensity of Light UNITSYMBOL Molemol Candela cd

  23. WHY IS THE SI SYSTEM SO IMPORTANT? • Read Mars Climate Orbiter article

  24. The SI system is easy to use because it is based on powers of ten. Prefixes are used with the names of the base units to indicate what power of ten should be used with the base unit.

  25. COMMON SI PREFIXES Multiplying Factor 10-1 10-2 10-3 10-6 10-9 10-12 Prefix deci centi milli micro nano pico Symbol d c m µ n p

  26. COMMON SI PREFIXES Multiplying Factor 101 102 103 106 109 1012 Prefix Deka Hecto Kilo Mega Giga Tera Symbol da h k M G T

  27. CONVERSIONS Kilo Multiply by 10 each step or move the decimal those many steps to the right Hecta Deka Base-m,s,L,g Divide by 10 each step or move the decimal those many steps to the left Deci Centi milli

  28. SCIENTIFIC NOTATION Scientific measurements are often very large or very small. In order to make these measurements easier to work with, measurements are often put in scientific notation.

  29. Numbers expressed in scientific notation always consist of a single whole number followed by decimal places and the exponent. 0.0000000244 = 2.44 x 10-8 2440000000000 = 2.44 x 10 12

  30. 0.0000000244 = 2.44 x 10-8 When decimal is moved to the right, the exponent is negative. 2440000000000 = 2.44 x 10 12 When decimal is moved to the left, the exponent is positive.

  31. ACCURACY Describes how close a measured value is to the true value of the quantity measured. Non accuracy arises due to – human error – line of sight- and instrument error. PRECISION Refers to the degree of exactness with which a measurement is made and stated. Lack of precision is due to limitations of the measuring instrument. NO MEASUREMENT IS PERFECT BECAUSE OF 2 FACTORS

  32. SIGNIFICANT FIGURES(HONORS ONLY) • Are those digits in a measurement that are known with certainty plus the first digit that is uncertain.

  33. RULES FOR DETERMINING SIGNIFICANT FIGURES (HONORS ONLY) 1. Zeros between other non zero digits are significant. 3.0025 has 5 Significant Figures 50.3 has 3 Significant Figures

  34. (HONORS ONLY) 2. Zeros in front of a non zero digit are non significant. 0.892 has 3 Significant Figures 0.0008 has 1 significant figure

  35. (HONORS ONLY) 3. Zeros that are at the end of a number and also to the right of the decimal are significant 57.00 has 4 Significant Figures 2.000000 has 7 Significant Figures

  36. (HONORS ONLY) 4. Zeros at the end of a number but to the left of a decimal are significant if they have been measured or are the first estimated digit; otherwise they are not significant. 1000 has 1 Significant Figure 20 has 1 Significant Figure

  37. GRAPHING

  38. GRAPHING

  39. GRAPHING Find the linear equation for the graph in the form y = mx + b Where: “y” is what’s on the y-axis “m” is the slope of the line “x” is what’s on the x-axis “b” is the y-intercept

  40. GRAPHING Slope (“m”) = rise/run = Dy/Dx Dy= 16 - 14.1 = 1.9 cm Dx= 30 – 5 = 25 s Slope = 1.9/25 = 0.076 = 0.076 cm/s Dy Dx

  41. GRAPHING Linear equation for the graph D = 0.076 t + 13.7 Test the equation to see if it is correct At t = 35 s what is D? D = 0.076 cm/s (35 s) + 13.7 = 16.4 cm

  42. Dimensional Analysis • In chemistry called Factor-Label method. • Dimensional analysis can eliminate invalid equations. • Dimensions can be treated as algebraic equations.

  43. Dimensional Analysis If I know 1 inch = 2.54 centimeters I can figure out how many centimeters are in 6.00 inches.

  44. Dimensional Analysis • How many m/s are you traveling if you are going 23 km/hr? • Answer: 23 km 1000 m 1 hr 1 min 1 hr 1km 60 min 60 sec = 6.39 m/s

  45. Practice How many seconds are in a year? Answer: 1 year 365 days 24 hrs 3600 sec 1 year 1 day 1 hr 31536000 = 3.15 x 107 s

  46. More Practice The average student is in class 330 min/day. a. How many hours/day is the average student in class? Answer: 330 min 1 hr 5.5 hrs/day 1 day 60 min b. How many seconds is the average student in class per week?

  47. Solving for the unknown 4) 5 = 5) = 2 6) = 1) x = 3 + 4 2) 4 = 8 – x 3) 2x – 6 = -3 15 x 5x + 2 6 2x + 3 x + 7 4 3

More Related