Physics 2240, Spring 2015

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2 Physics 2240, Spring 2015 Instructor Drew Von Maluski UW-Platteville Office: Engineering Hall 227 Office Hours: Open Door Policy Tentative Scheduled Office Hours: Monday 9 11am Tuesday 10am noon Wednesday 11am-noon, 2pm 3pm Thursday 9 11am Friday 9 11am or by appointment. 2

3 About Me 3

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10 About Me: About You? 10

11 Text: University Physics by Young and Freedman 13th ed. At Textbook Center. 029 Dounda Hall 11

12 Alternate Text Physics for Scientists and Engineers 2nd ed by Knight. (homework is from this book) Textbook Center has used 1 st edition copies available to Purchase for 1$. 12

13 Another good book Fundamentals of Physics by Halliday / Resnick / Walker 13

14 Grading: Lecture 75%, Lab 25%. Your lecture grade will comprise of: *Homework and class participation (subjectively given) (30% + 10%) *Exams (60%) Some Important Remarks: * Due to the amount of material to be covered in this course the pace might be fast at times. And since later sections depend on ideas covered earlier, it is important not to fall behind. * You are expected to read the sections we will be covering in lecture before/after you come to class. We will not have time to cover all the examples from the text, but you are still expected to read the whole section yourself and be familiar with it. You are always welcome to discuss the material with me. * Please let me know in advance of any special circumstances which may prevent you from attending classes. * Help each other out and discuss difficulties, but do your own work (!). 14

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18 To Do: Read Chapter 1 Start working on Homework #1 18

19 Start Ch1 & Ch3 Concepts of motion Vectors and Coordinate Systems 19

20 Scientific Notation # x 10 # Instead of 320,000 > 3.2 x 10 5 Instead of > 8.75 x

21 Working with Scientific Notation 21

22 Why Scientific Notation? 9.46 x Or googol = 1.0 x Or 10,000,000,000,000,000,000,000,000,000,000,000,000,000,0 00,000,000,000,000,000,000,000,000,000,000,000,000,000,0 00,000,000,000,000,

23 Bad notation 1 x *10 7 1E7 1e7 good notation good notation bad bad Recall that e = E is often shorthand for Exp(), the exponential 23

24 Bad Notation cont. 1 x good not nice 10 7 = 1 x 10 7 It is not 10 x 10 7 Careful: Books sometimes use this notation. 24

25 Units Different systems of Units. Imperial: Inches, feet, yards, miles ounces, pounds, tons fluid ounce, pint, quart, gallon Metric: centimeter, meter, kilometer milligram, gram, kilogram milliliter, liter, kiloliter 25

26 Systems Compared 1mi = 1760 yards = 5,280feet = 63,360inches vs 1km = 1,000m = 100,000cm = 1,000,000mm 1ton = 2,000 pounds = 32,000 ounces vs 1kilogram = 1,000gram = 1,000,000 milligram 1 US ton = 2,000 lbs, 1 British ton = 2240 lbs, 1 metric ton = 2204 lbs 26

27 SI Units (Metric) Fundamental Units: MKS Meter, Kilogram, Second (Length, Mass, Time) 27

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29 Working with Units 29

30 Unit Conversion If two things are equal, form a fraction. 1 km = 1000m or Remember: You can always multiply things by 1 without changing it! 30

31 Example 1 hour = 60 minutes, 1 minute = 60 seconds 31

32 Working with Higher Power Units 32

33 Working with Units 33

34 Scalars Def: A scalar is a number, possibly with units. Examples: 3, 7, 10 miles, 5 seconds, 12.5 pounds 34

35 Vectors Def: A vector is a number with direction, usually with units. Ex: 3 miles north, 2 miles per hour in the left direction, 6.5 meters per second at 37 North of East. 35

36 Notation: # at Angle Direction of Direction Ex: 3 feet at 60 South of West Start at second Direction, and turn toward the first direction by the angle amount. 36

37 Notation: If given a direction like: southwest, northeast, northwest, or southeast, assume it is at a 45 angle between the two. Ex: 1 mile northeast is the same as 1 mile at 45 North of East. 37

38 Drawing Vectors A vector is drawn by a straight arrow pointing in the direction of the vector. The length of the arrow is proportional to the size of the vector. 38

39 Drawing Vectors 8 miles northeast 4 miles northeast 4mi 8mi 39

40 Adding Vectors (by drawing) Tip to Tale Method: Put the tip of one vector to the tail of the other vector. The new vector extends from the tail of the first vector to the tip of the second. 40

41 Adding Vectors (by drawing) 41

42 Subtracting Vectors Subtracting is the same as adding the negative. A negative vector is the same size vector, but opposite direction. 42

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44 Multiplying by a scalar 44

45 Vector Components Recall Trig: Sin (θ ) = Opposite Hypotenuse Cos (θ ) = Adjacent Hypotenuse Tan (θ ) = Opposite Adjacent 45