VectorsWhat is a Vector?Vector NotationSlide 4Equivalent VectorsFind the VectorFundamental Vector OperationsVector AdditionVector SubtractionVector Addition / SubtractionMagnitude of a VectorUnit VectorsSlide 13Finding the ComponentsAssignment Part AApplications of VectorsApplication of VectorsDot ProductFind the Dot (product)Dot Product FormulaFind the AngleDot Product Properties (pg 321)Assignment BScalar ProjectionSlide 25Parallel and Perpendicular VectorsWork: An Application of the Dot ProductAssignment CVectorsLesson 4.32What is a Vector?A quantity that has bothSizeDirectionExamplesWindBoat or aircraft travelForces in physicsGeometricallyA directed line segmentInitial pointTerminal point3Vector NotationGiven byAngle brackets <a, b> a vector with Initial point at (0,0)Terminal point at (a, b)Ordered pair (a, b)As above, initial point at origin, terminal point at the specified ordered pair(a, b)4Vector NotationAn arrow over a letteror a letter in bold face VAn arrow over two lettersThe initial and terminal points or both letters in bold face ABThe magnitude (length) of a vector is notated with double vertical linesVurVABABuuur5Equivalent VectorsHave both same direction and same magnitudeGiven pointsThe components of a vector Ordered pair of terminal point with initial point at (0,0) (a, b)( ) ( ), ,t t t i i iP x y P x y,t i t ix x y y- -6Find the VectorGiven P1 (0, -3) and P2 (1, 5)Show vector representation in <x, y> format for <1 – 0, 5 – (-3)> = <1,8>Try theseP1(4,2) and P2 (-3, -3)P4(3, -2) and P2(3, 0) 1 2PPuuuur7Fundamental Vector OperationsGiven vectors V = <a, b>, W = <c, d>MagnitudeAddition V + W = <a + c, b + d>Scalar multiplication – changes the magnitude, not the direction3V = <3a, 3b> 2 2V a b= +8Vector AdditionSum of two vectors is the single equivalent vector which has same effect as application of the two vectorsABA + BNote that the sum of two vectors is the diagonal of the resulting parallelogramNote that the sum of two vectors is the diagonal of the resulting parallelogram9Vector SubtractionThe difference of two vectors is the result of adding a negative vectorA – B = A + (-B)AB-BA - B10Vector Addition / SubtractionAdd vectors by adding respective components<3, 4> + <6, -5> = ?<2.4, - 7> - <2, 6.8> = ?Try these visually, draw the resultsA + CB – AC + 2BABC11Magnitude of a VectorMagnitude found using Pythagorean theorem or distance formulaGiven A = <4, -7>Find the magnitude of these:P1(4,2) and P2 (-3, -3)P4(3, -2) and P2(3, 0) 2 24 ( 7)A = + - =12Unit VectorsDefinition:A vector whose magnitude is 1Typically we use the horizontal and vertical unit vectors i and ji = <1, 0> j = <0, 1>Then use the vector components to express the vector as a sumV = <3,5> = 3i + 5j13Unit VectorsUse unit vectors to add vectors<4, -2> + <6, 9>4i – 2j + 6i + 9j = 10i + 7jUse to find magnitude|| -3i + 4j || = ((-3)2 + 42)1/2 = 5Use to find directionDirection for -2i + 2j( )2tan234qpq-==14Finding the ComponentsGiven direction θ and magnitude ||V||V = <a, b>6V =bacossina Vb Vqq= �= �6pq =15Assignment Part ALesson 4.3APage 325Exercises 1 – 35 odd16Applications of VectorsSammy Squirrel is steering his boat at a heading of 327° at 18mph. The current is flowing at 4mph at a heading of 60°. Find Sammy's courseNote info about E6B flight calculatorNote info about E6B flight calculator17Application of VectorsA 120 pound force keeps an 800 pound box from sliding down an inclined ramp. What is the angle of the ramp?What we haveis the forcethe weightcreatesparallel to theramp18Dot ProductGiven vectors V = <a, b>, W = <c, d>Dot product defined asNote that the result is a scalarAlso known asInner product orScalar productV W a c b d= �+ �g19Find the Dot (product)Given A = 3i + 7j, B = -2i + 4j, and C = 6i - 5j Find the following:A • B = ?B • C = ?The dot product can also be found with the following formulacosV W V W a= � �g20Dot Product FormulaFormula on previous slide may be more useful for finding the angle coscosV W V WV WV Waa= � �=�gg21Find the AngleGiven two vectorsV = <1, -5> and W = <-2, 3>Find the angle between themCalculate dot productThen magnitudeThen applyformulaTake arccosVW22Dot Product Properties (pg 321)CommutativeDistributive over additionScalar multiplication same over dot product before or after dot product multiplicationDot product of vector with itselfMultiplicative property of zeroDot products ofi • i =1j • j = 1 i • j = 023Assignment BLesson 4.3BPage 325Exercises 37 – 61 odd24Scalar ProjectionGiven two vectors v and wProjwv = vwprojwvThe projection of v on wcosv a�25Scalar ProjectionThe other possible configuration for the projectionFormula used is the same but result will be negative because > 90°vwprojwvThe projection of v on wcosv a�26Parallel and Perpendicular VectorsRecall formulaWhat would it mean if this resulted in a value of 0??What angle has a cosine of 0?cosV WV Wa�=�0 90V WV Wa�= � =�o27Work: An Application of the Dot ProductThe horse pulls for 1000ft with a force of 250 lbs at an angle of 37° with the ground. The amount of work done is force times displacement. This can be given with the dot product37°W F s= �cosF s a= � �28Assignment CLesson 4.3CPage 326Exercises 63 - 77 odd79 – 82
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