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Graphs of acceleration, velocity, position

  1. Sep 5, 2013 #1
    im confused with finding the max velocity , acceleration, and position.
    Usually in these types of problems I'm given a function, and an interval and have to find the max acceleration or velocity.

    Sometimes a negative number comes up which is greater in magnitude than the other numbers, and that is the answer. I don't get why. Can someone please explain?
    Sorry if I'm being vague, i can't really explain it too well.
     
  2. jcsd
  3. Sep 5, 2013 #2

    mfb

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    2016 Award

    Staff: Mentor

    I don't see what would be special about a negative number. Negative and positive are arbitrary anyway, you could measure in the other direction and all signs would get swapped.
     
  4. Sep 5, 2013 #3
    Like mfb said, it's about directions.

    Consider a horizontal line (which is 1-dimensional) and define a particular position, (i.e. point) as (0): all the positions (points) to the left of (0) will be negative, and all the positions (points) to the right of (0) will be positive.

    • A negative position will mean a position to the left of (0), a positive position will mean a position to the right of (0).
    • A negative velocity will mean motion to the left along the line, a positive velocity will mean motion to the right.
    • A negative acceleration will mean acceleration to the left along the line, a positive acceleration will mean acceleration to the right.
    The same applies for 2-dimensional and 3-dimensional space too. Velocity and acceleration (and forces etc.) are vector quantities. Vectors have both magnitude and direction. See Euclidean vector.

    See also:


    A 2-D graph with velocity vectors (example):
    Acceleration.JPG
     
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