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Graphing one dimensional motion. Position-Time Velocity-Time. Position-Time Graphs. Plot displacement vs time helps estimate position in between data points Slope=velocity +/- of slope=direction slope=speed.
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Graphing one dimensional motion Position-Time Velocity-Time
Position-Time Graphs • Plot displacement vs time • helps estimate position in between data points • Slope=velocity • +/- of slope=direction • slope=speed
Who is at rest? Traveling slowly in + direction, traveling quickly in negative direction? Traveling quickly in + direction? http://dev.physicslab.org/Document.aspx?doctype=5&filename=Kinematics_ConstantVelocityPositionTimeGraphs1.xml
Position-Time graphs with acceleration • If object is accelerating, slope of p-t graph will change
p-t graphs • Which object(s) are maintaining constant v? • Which are accelerating? • Which is changing direction? • Which is fastest? • Which is slowest? • Which has greatest acceleration?
Try some… • Sketch a position-time graph for an object which is moving with a constant, positive velocity
Try more… • Sketch a position-time graph for an object moving in the - direction and accelerating from a low velocity to a high velocity
Velocity-time graphs • Velocity-time graphs slope=acceleration • Slope = v/t • If velocity is +, line will be in + part of graph • If velocity is -, line will be in - part of graph
v-t graphs • If + velocity and accelerating in the + direction, slope will be + in the + part of graph • If + velocity and accelerating in the - direction, slope will be - in the + part of graph
v-t graphs • Which is maintaining v? • Which is accelerating? • Which is not moving? • Which is changing direction? • Which has greatest v? • Which has greatest a?
What if a is not constant? • If a is increasing, slope of line is increasing • Watch out for - and + parts of graph denoting +/- velocity
Try some velocity-time • Sketch a velocity-time graph for an object moving in the + direction, accelerating from a fast speed to a slow speed
Try more… • Sketch a velocity-time graph for an object which first moves with a constant speed in the + direction, and then moves with a negative acceleration