Describing Motion with Diagrams • Ticker Tape Diagrams
Ticker Tape Diagrams The distance between dots represents the object’s change in position during that time interval
Ticker Tape Diagram A changing distance between dots indicates a changing velocity – acceleration
Graphing Motion ZERO 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 0 Sketch above graphs
Graphing Motion Uniform 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 acceleration
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 graph • Acceleration will always be a horizontal line
Position time graph x Tangent Lines t On a position vs. time graph:
Position time graph x t Increasing & Decreasing Increasing Decreasing On a position vs. time graph: Increasing means moving forward (positive direction). Decreasing means moving backwards (negative direction).
Position time graph x t Concavity On a position vs. time graph: Concave up means positive acceleration. Concave down means negative acceleration.
Describe the motion • This 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).
Area under a v vs t graph The area of a v vs t graph is displacement