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1、Distance SpeedTime*These are all scalar quantities-only magnitudeDisplacementVelocityAcceleration *These are all vector quantities-magnitude and directionDISTANCETotal traveledPath dependentScalar quantity Both use the same variable and unitsVariable: d (sometimes: x,r,)Units: mDISPLACEMENTChange in
2、 positionPath independentVector quantityAn odometer in your car shows:Distance The following is a list of gains and loses of a Bears possession First down: gain 8 yardsPenalty lose 10 yardsSecond down: gain 11 yardsThird down: lose 1 yardWhat is the total distance?What is the total displacement?DIFF
3、ERENCESSpeed: how fast (scalar)Always positiveExample: 25 m/sVelocity: how fast in a certain direction (vector)Can be positive or negativeExample: 25 m/s NorthSIMILARITIESVariable: vUnits: m/sA speedometer in your car shows:SpeedJim travels from Palatine to Chicago at 65 mph. Susie travels from Chic
4、ago to Palatine at 65 mph. Are the velocities equal?No, different directionsv=(df-di)/(tf-ti)OR commonly written asv=d/ t* means changeAverage Speed/VelocityIn gym, you have to run the 100 m dash. If you run it in 18 s, what was your velocity?A freaky fast Jimmy Johns delivery man makes a delivery t
5、hat is 2.2 miles away and it takes him 9 min. What is his average velocity in mi/hr? SPEED (AVERAGE)Total distance traveled divided by the total time elapsed*Example: Round trip drive to schoolVELOCITYTotal displacement divided by total timeA change in velocity Vector quantity Positive vs. Negative
6、Acceleration+ velocity and + acceleration = _+ velocity and - acceleration = _ - velocity and - acceleration = _- velocity and + acceleration = _Variable: aUnits: m/s/s or m/s2Equation:a=(vf-vi)/(tf-ti)OR commonly written as:a= v/ tName 3 ways to accelerate your car:1.Step on gas pedal2.Step on brak
7、e pedal3.Turn steering wheelA car accelerates from a stop sign up to a speed of 11 m/s. If it takes 4 to do so, what is the cars acceleration?Problem 1:How long does it take a turtle to travel 1,000 m if it can travel at a pace of 1.3 m/s?Problems 2:What is the change in velocity if an object accele
8、rates at 2 m/s2 for 4.5 seconds? If the object started at 3 m/s, what is its final speed?DISTANCE VS. TIME GRAPHSVELOCITY VS. TIME GRAPHSSlope is accelerationSlope = rise/run = velocity/time = ACCELERATION Area under graph is distance traveledArea = base*height = velocity*time = DistanceSlope is vel
9、ocitySlope = rise/run = distance/time = VelocityStraight Lines CONSTANTCurving Lines CHANGINGFlat Line - ZEROSteeper the slope, the higher the valueDefinition of average velocity: (vi + vf)/2Distance = rate * time: d=vavg*tDefinition of acceleration (final velocity): vf=vi + atTimeless: vf2=vi2 +2ad
10、Position: d=vit +1/2at2EquationxvivftaDefinition of average velocity: vavg=(vi + vf)/2Distance = rate * time:x=vavg*tDefinition of acceleration (final velocity): vf=vi + atTimeless:vf2=vi2 +2axPosition:x=vit +1/2at2Identify givensLook for hidden givensIdentify unknown(s)Compare givens and unknowns t
11、o equationsIn the beginning: chartRe-read problem if stuck*always show your work (G.U.E.S.S.)What is Starlin Castros acceleration as he runs toward first base if he reaches the base with a speed of 6.5 m/s? The distance between the plates is 27.432 meters .An airplane can accelerate at a rate of 4.9
12、m/s2. If it takes 45 s for the plane to start to elevate and the plane starts from rest, what is the minimum length of runway required?Seeing a stop sign ahead, a person begins to brake as they drive lawfully on Cunningham. If their reaction time is 1 s, what is the total distance they need to stop if they can accelerate at -8 m/s2?谢谢你的阅读v知识就是财富v丰富你的人生END
