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Homework Help: Postion-Time Graphs

  1. Mar 23, 2005 #1
    Hi! I' having a bit of trouble with position-time graphs. I know how to use a velocity-time graph to make a postion time graph, but how can you tell, using velocity-time, if hte object is moving backward (past the point where it began)?
  2. jcsd
  3. Mar 24, 2005 #2


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    I assume you're talking about motion in a straight line. It's easy to tell on a v-t graph if an object is moving backward: the velocity will be negative on the graph when this is the case.

    As for when the object passes its starting point: that depends on for how long it has been travelling in the 'backwards' phase, which you can only tell by integrating (i.e. finding the area under the curve), and seeing whether the total displacement is in the positive or negative direction.
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