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MondayQuestion of the Day: What is the difference between velocity and speed? Agenda:QuizestCornell NotesHomeworkDo Now: Grab your personal scantronTurn in your Magnetism work packetClear your deskHomework:(7) Reading Log 4: pg 313-315(8A) Problems pg 318

Trip to Stanford: Campus Tour and Mens Basketball Game!When: Saturday, January 14thStanford vs. Colorado

To enter the lottery to win a ticket, email Ms. Gamm your name and period by Monday January 9th

I will use excel to randomly pick 2 students Lab CorrectionsDue Friday

Common lab misconceptions: changing voltage automatically changes current add a coil to increase B-fieldMoving charges have E & B fields DO NOT WRITE ON YOUR TESTWhen you are done with your test:Make sure your test version (A or B?) is written on your scantronBring your test & Scantron to meStart Reading Log pg 313-315

Linear Motion5Fastspeeddepends on distance and time average speeduses total distance and total time

6Frame of Referencespeed is relativeF.o.R. is something to compare speed toHow fast are you moving now?Earth is rotating at 1,000 mph

7Frame of ReferenceEarth is orbiting sun at 66,000 mphEverything in universe is moving

8Frame of ReferenceSo, if you drive 55 mph, you are going 55mph relative to the earthUniverse speed limit: speed of light 3 x 10 8 m/sIs car moving?

9VelocityScalar vs. Vectorscalar: measures only the amountex: temperature, area, distance traveled vector: measures both amount and directionvector: scalar and directionex: weightin which direction is weight directed?10

Displacementspeed = distance / timevelocity = displacement / timedistance: log of total miles traveleddisplacement: change in positiondisplacement: distance from start to end

arrows mean they are vectors

distancedisplacement11Time to PracticeGo to pg. 31812TuesdayQuestion of the Day: What is the difference between velocity and speed? Agenda:Check yourselfStart HomeworkHomeworkDo Now: 1. Graph your Quizest score on your tracker!2. Check yourself page 316-317Work in PairsWrite a short explanation for each QuestionFirst 4 pairs to finish receives 3 tickets!Homework:(8B) Problems pg 319-321 (14 & 15 Honors only) Quizest Corrections & retakeCome in after school to do corrections (Due Friday)If you do corrections, you receive the higher of the two scoresIf you dont, you receive the averageRetake on Friday in room 308Tuesday TutoringStop by if you need homework helpOr converting help Check Yourself pg 316-317BABABABCBCABABBStart pg 319-321Remember conversions!8. Convert minutes to hours9. Convert m to mi (1 mi = 1609 ft) and mach speed = 331 m/s10. Convert feet to miles (1 mi = 5280 ft) and seconds to hours12. Convert km to mHomework Answers pg 318Distance is same, but displacement is shorter on track B, thus B is faster2A.) Vbicycle = 8 mph, Vwest = 21 mph, Veast = 39 mph2B.) Vboy = 39 mph, Vbicycle = 47 mph, Vwest = 60 mph3.) Any straight line motion in one direction4.) Any trip where you finish where you started and moved some distance5A.) 12 blocks 5B.) 4 blocksHomework Answers pg 3196.) Vavg = 6.25 m/s7A.) Vavg = 26 mph7B.) = 2 mph8.) Vavg = 66 mph9.) t = 1.6 minutes10.) 6 mph over the speed limit11.) saves 5.2 minutes12.) wait 210 s

Homework Answers pg 32013A.) Vavg = 38 mph, 13B.) = 27 mph 14.) v = 21 m/s15.) d = 0.83 mi

Graphing RulesUse a ruler (straightedge)!Label your axes!(units in parentheses)time is always below

Time (s)VariableUnit

Distance (m)Graphing Rules3.Title the graph!(Y vs. X)Distance vs. TimeTime (s)Distance (m)Graphing Rules4.SCALE. Stretch out your axes!Graphing Rules5. Use a Pencil!!6. Do not just connect the dots!Line of best fit curve: smooth line: rulerthey might not touch dots24Add scale consistency and line examples

Graphing RulesDrawing tangent linesdrawn at a pointbalance ruler on curve perpendicular with normalDistance vs. TimeTime (s)Distance (m)make it long enough to find the slopeAhh. Just right!Graphing

26Add scale consistency and line examplesMoviesAnd now for a short movie27Add scale consistency and line examplesEureka: Inertia

28Eureka: Mass

29Eureka: Speed

30LabetteGraphing Motionpg. 30531Add scale consistency and line examplesAccelerationacceleration the rate of change of velocity

final velocity initial velocityrefers to speeding up and slowing down or

arrows mean

32ExampleA car moving at 20 m/s comes to a stop in four seconds. What was the cars acceleration?Given:

Want:

33Example solve for acceleration

said negative five meters per second per secondnegative acceleration meansslowing down34

35Accelerationyou feel speed when you accelerateThis includes speeding up, slowing down and sharp turns at constant speed!All three are accelerations

36Eureka: Acceleration I

37Speed vs. Time Graphslook at the slope

units are m/s/s=m/s2

acceleration!

same answer as example

38Speed vs. Time Graphs

So, to summarize the graphs: For distance vs. time:slope = speedFor speed vs. time:slope = accelerationarea under line = distance covered39Eureka: Acceleration II

40Freefallfreefall objects moving under only force of gravity

terminal velocity when air resistance becomes equal to gravity

due to gravity = g

g = 9.8 m/s2

41Freefalllets look at the motion of three objects

one dropped from restone thrown downwardsone thrown upwards

All of these motions are types offreefall!42Freefalllets look at the motion of three objects

one dropped from restone thrown downwardsone thrown upwards

All of these motions are types offreefall!43Eureka: Gravity

44LabAcceleration due to Gravitypg. 31445Add scale consistency and line examples

Putting it togetherLets use what we know about graphs to make two more formulas.Lets look at the graph from ti to tf

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Putting it togethereach time matches up with a velocityFirst velocity is vi and last is vf

vi

vf47

Putting it togetherTo find distance: area under the linetwo shapes: triangle and rectangle

vi

vf48

Putting it togetherd = area of rectangle + area of trianglearea of rectanglearea of triangle

vi

vf

49Putting it together

we now have a connection between a and d50Putting it togethersolve for t from first a equationsubstitute into second a equationa little fancy algebra and

nice if you do not have t51Putting it togetheruse equation 1 only if acceleration is zerouse equations 2-4 only if constant acceleration

52Putting it togethernotice there are no arrowsthey are still all vectors

53Putting it togethervectors mean that direction is importantex. positive for up, negative for down

54ExampleA spear is thrown down at 15 m/s from the top of a bridge at a fish swimming along the surface below. If the bridge is 55 m above the water, how long does the fish have before it gets stuck?Given:

Want:

why negative?

55Example

Which equation has vi, d, a and t?Eqn 3 works, butyou would need quadratic (bleh!)

Eqn 2 would work if we had vf. Eqn 4 can get us vf!

56Example

First, eqn. 4

positive or negative?

57Example

solve for t in eqn 2.substitute vf into eqn 2.

58Check YourselfTurn to pg. 32159

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