Presentation on theme: "Chapter 11 – Part 1 Non-accelerated Motion Chapter"— Presentation transcript:
1 Chapter 11 – Part 1 Non-accelerated Motion Chapter 11.1-11.2 Physical ScienceChapter 11 – Part 1Non-accelerated MotionChapter
2 Frame of ReferenceA system of objects that are not moving with respect to one anotherA reference point or systemBASICALLY …. Something unchanging to measure things fromGood frames of reference for measuring the motion of a car…The Earth, the road, buildings, treesBad frames of reference for measuring the motion of a car….Clouds, other cars on the road, bikers, flying birds
3 Relative Motion Movement in relation to a frame of reference All Motion is RelativeThis means… all motion is based on someone’s or something’s perspectiveExamplesSchool bussesCars on highwayLabQuest
5 Measuring Distance Length of a path between two points When an object moves in a straight line, the distance is the length of a line connecting the starting point and the ending pointSI Unit – metersOther options- km, mi, cm
6 Displacement Distance with a direction How much an object is displaced Distance – 5 kilometersDisplacement – 5 Kilometers NorthHow much an object is displacedWhen objects travel in a straight line the magnitude (amount) of the displacement is equal to the distance travelledWhen an object does not travel in a straight line, distance and displacement will be different
8 Vectors Scalar Quantities Vector Quantities 3 km + 3 km = 6 km Have magnitude and directionScalar QuantitiesOnly have magnitudeVector quantities can be represented with arrows of a scaled lengthLength shows magnitudeArrow shows direction3 km3 km3 km + 3 km = 6 km
9 Vectors & Scalars Scalars- Have only Magnitude Vectors- Have Magnitude & DirectionScalars-Have only MagnitudeExamplesDisplacementDistanceVelocitySpeedAccelerationMassForceTime
10 Displacement in a straight line 4 km7 km4 km + 7 km = 11 km8 km5 km8 km - 5 km = 3 km
11 Displacement that isn’t on a straight Path Resultant Vector (red) – vector sum of 2 or more vectors3 km5 km2 kmFinding Distance Using Scalar Addition = 7 kmFinding Displacement using Vector Addition = 5 km NE1 km1 km
12 These two vectors have the same ________________ and opposite ________________.
13 These two vectors have different ________________ but the same ________________.
14 These two vectors have the same ________________ AND the same ________________.
15 average SpeedAverage Speed is equal to distance divided by time𝑣 𝑎𝑣𝑔 = 𝑑 𝑡How fast or slow something is goingA rate of motion
16 Instantaneous Speed Speed at a given moment of time What the speedometer on a car reads
17 Constant Speed When speed is not changing Instantaneous speed is equal to average speed at all timesNOT Speeding up or slowing downOnly ways to change speed is to speed up or slow down
18 Average Speed Constant Speed Instantaneous Speed The Average speed over some timeMaintaining the same speed all the timeSpeed of an object at a particular moment in time
19 Velocity Speed AND direction that an object is moving Vector Quantity + or – sign indicates which direction the velocity is+ means North, Up, East, or to the Right- means South, Down, West, or to the leftSometimes multiple velocities can affect an objects motionSailboat, airplanesThese velocities combine with Vector Addition
20 Speed vs. Velocity Speed – tells how fast something is moving Ex km/hrVelocity – tells how fast something is moving and its directionEx. 35 mph NorthCan an object move with constant speed but have a changing velocity?Can an object move with constant velocity but have a changing speed?
21 2 ways to change Speed3 ways to change VelocitySpeed UpSlow DownChange Direction
22 acceleration Acceleration – The rate at which velocity changes Can be described as ….Changes in SpeedChanges in DirectionOR change in both Speed and DirectionVector QuantityUnits are meters per second per second or m/s2
23 3 Way to AccelerateSpeed UpSlow DownChange Direction
24 Can an object moving with constant speed be accelerating?
26 Calculating Acceleration 𝑎= 𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑡𝑜𝑡𝑎𝑙 𝑡𝑖𝑚𝑒 = ∆𝑣 𝑡 = 𝑣 𝑓 − 𝑣 𝑖 𝑡Divide the change in velocity by total time
27 ExampleA car starts from rest and increases its speed to 25 m/s over the course of 10 seconds. What is the car’s acceleration?𝑎= 𝑣 𝑓 − 𝑣 𝑖 𝑡 𝑣 𝑖 =0 𝑚 𝑠 𝑣 𝑓 =25 𝑚 𝑠 𝑡=10 𝑠𝑒𝑐𝑎= (25 𝑚 𝑠 − 𝑚 𝑠 ) 10 𝑠𝑒𝑐 =2.5 m 𝑠 2
31 Graphs of motion Motion can also be depicted very well using graphs Two types of graphsDisplacement vs. time (D-t) graphsVelocity vs. time (V-t) graphsStraight,upward line on a V-t graph means constant accelerationStraight,upward line on D-t graph means constant velocityDisplacement (m)
32 D-t graph of constant ‘v’ Displacement increases at regular intervals, so constant velocityGraph below Increases displacement by 5 meters every sec.To find vel. on a disp.- time graph, find Slope
33 Slope 5 m/s Rise/run=slope= 25/5 = Rise = 25 Run = 5 Tells the rate of increase of the y-value as you move across the x values for any graphSlope = rise / runIn other words… how much the graph goes up divided by how much the graph goes acrossSlope tells us properties of the motion being depictedOn a displacement time graph slope = velocityOn a velocity-time graph slope = accelerationRise/run=slope= 25/5 =5 m/sRise = 25If you took slope of smaller sections of the graph you would get the same answer since ‘v’ is constantRun = 5
38 Velocity- Time graphsv v. t graphs may look the same as some D v. t graphs, but the motion they describe can be very different because they deal with velocity, not distance.**The slope, of a Velocity v. Time graph indicates Acceleration**.
40 Distance-time graph of changing velocity Time (s)Displacement (m)18211318415525What is v for 0-1 sec.??What is v for 0-2 sec.??What is v for 3-5 sec.??What is v for 0-5 sec. ??
41 Distance-time graph of constant acceleration Parabola….. If + acc, line keeps getting steeper and steeperdt
42 Avg. velocity from 0-1 sec. ? 4 m/s Avg. vel. From 3-4 sec? 16.5Acc. From 2-3 sec? 7 m/s2
43 Velocity vs. Time graph of constant acceleration Velocity (m/s)
44 Position –time Graph Slope = rise/run … Rise = Run = Rise/run = 50 5 10 m/s = speedSpeed-time graphSlope = rise/run …Rise =16Run =4Rise/run =4 m/s = acceleration
45 Free Fall Acceleration As objects fall toward the Earth they are accelerating at a rate of 9.8 m/s2 downwardWe can usually round 9.8 m/s2 to 10 m/s2Objects in free fall will gain 10 m/s of speed for every 1 second it is fallingTime (sec)Instantaneous Speed (m/s)Acceleration (m/s2)101220330440
46 Free Fall Acceleration Object is in free-fall any time it is ONLY under the influence of gravityIncluding when something is thrown upwardsAll objects (regardless of mass) fall at the same rate on Earth, when air resistance is ignoredBall thrown upward with initial velocity of +30 m/sTime (sec)Instantaneous Vel. (m/s)Acceleration (m/s2)+30-101+202+10345-206-30