2 Describing Motion with Diagrams Ticker Tape DiagramsA long tape attached to a moving object and threaded through a device that places a tick upon the tape at regular intervals of time – leaving a trails of dots
3 Ticker Tape DiagramsThe distance between dots represents the object’s change in position during that time intervalsmall distance – slow moving Even distances = constant velocitylarge distance – fast moving
4 Ticker Tape DiagramA changing distance between dots indicates a changing velocity – acceleration
6 Graphing MotionZERO MOTION The object is at rest Position-time graph (x vs t) position of an object remains constant over time Velocity-time graph (v vs t) object is not moving, it has 0 velocity Acceleration-time graph (a vs t) If the object’s velocity is not changing, its acceleration is 0The acceleration is zero because velocity is not changing not because the velocity is zeroSketch above graphs
7 Graphing MotionUniform Motion – Constant Velocity x vs t graph as time increases so does the position *slope of a x vs t graph = velocity v vs t graph velocity remains constant over time *this should reflect the value of the slope of the x vs t graph a vs t graph velocity is not changing, acceleration is 0 *slope of a v vs t graph is accelerationSteeper slope – faster velocityShallow slope – slower velocity
8 Graphing Motion Uniform Accelerated Motion x vs t graph – position is increasing exponentially with time (acceleration)v vs t graph – velocity is increasing with time (acceleration)a vs t graph – acceleration is constant.The value of a is equal to the slope of the v vs t graphAcceleration will always be a horizontal line
9 Tangent Lines t On a position vs. time graph: SLOPE VELOCITY Positive Position time graphxTangent LinestOn a position vs. time graph:SLOPEVELOCITYPositiveNegativeZeroSLOPESPEEDSteepFastGentleSlowFlatZero
10 Increasing & Decreasing Position time graphIncreasing & DecreasingtxIncreasingDecreasingOn a position vs. time graph:Increasing means moving forward (positive direction).Decreasing means moving backwards (negative direction).
11 Concavity On a position vs. time graph: Position time graphtxConcavityOn a position vs. time graph:Concave up means positive acceleration.Concave down means negative acceleration.
12 Describe the motionThis object is moving in the positive direction and accelerating in the positive direction (speeding up).This object is moving in the negative direction and accelerating in the negative direction (speeding up).This object is moving in the negative direction and accelerating in the positive direction (slowing down).