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Homework Help: Graphs of a vs. t, v vs. t, and d vs. t ?

  1. Sep 1, 2003 #1
    Graphs of a vs. t, v vs. t, and d vs. t ???

    Plese help !!

    I am given a graph of a vs. t
    How do i use it to determine the other graphs:
    v vs. t
    d vs. t
  2. jcsd
  3. Sep 1, 2003 #2


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    Science Advisor

    You haven't supplied enough information. What are the relationships between the variables defined by the letters a,t,v,d?
  4. Sep 1, 2003 #3


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    Staff: Mentor

    If you have the equations, just plug in a few points and go.

    If you have one equation, you integrate to get the others... but like mathman said, you haven't given us enough information.
  5. Sep 1, 2003 #4
    i am not given any equations
    i am only given the graph of a vs. t
    plz help
  6. Sep 1, 2003 #5


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    Staff Emeritus
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    Gold Member

    You need to use the basic relationships between the quanities.

    a= dv/dt => The acceleration determines the slope of the velocity graph. So a constant acceleration line means an increasing velocity, Acceleration = 0 means a constant velocity. You must study the graphs you are given and piece together the various graphs.

    Remember that v = dx/dt so you can do the same thing with the velocity line to create a displacement graph.

    With that said this is off to homework.
  7. Sep 1, 2003 #6
    v = [inte] a dt

    d = [inte] d dt
  8. Sep 2, 2003 #7
    If it's not a very screwed up graph you can write the equations just by looking at it.
  9. Sep 2, 2003 #8
  10. Sep 2, 2003 #9


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    Science Advisor

    Probably what you want for this is the fact that the integral is the area under the curve.

    Given a graph for a(t), estimate the area under the curve from 0 to t for a number of different values of t. That will give the graph for v(t). It is probably enough to remember things like: if the graph of a(t) is above a=0, then v(t) is increasing, if below, then v(t) is decreasing. if the graph of a(t) is horizontal, then v(t) increases (or decreases) linearly with slope given by the a value.

    Once you have a rough graph for v(t), x(t) is the area under that curve. Repeat the process to get a graph of x(t).
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