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Homework Help: Help with simple vector graph

  1. Oct 27, 2011 #1
    Hi guys - i need some help with a really simple problem. I've just started doing physics in college, and I've had a homework question that just doesn't work out for me (I also have the answers).

    A particle moves in a straight line with a constant velocity of 5m/s for 2 seconds. It then moves with a constant acceleration of -2m/s^2 for 8 seconds. Sketch a velocity-time graph for the interval of 10 seconds and find:

    a) the final velocity
    b)the total distance covered by the particle
    c)the increase in displacement of the particle

    i'm getting -10m/s for a - then 44.5m for b.

    Could someone tell me if I'm atleast heading in the right direction? (no pun intended)
     
  2. jcsd
  3. Oct 27, 2011 #2

    PeterO

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    If the initial velocity is 5 [given] and the final velocity is -10 [your calculation] then the change is -15.

    AN acceleration of -2 for 8 seconds does not give -15 .
     
  4. Oct 27, 2011 #3
    If I know my vector is -2m/s^2 then - how will I work out the final velocity of that vector from that?
     
  5. Oct 27, 2011 #4

    PeterO

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    Why did you say your vector was -2 m/s2?

    Surely you meant your acceleration was -2 m/s2.
     
  6. Oct 27, 2011 #5
    Isn't the vector describing an acceleration?
     
  7. Oct 27, 2011 #6

    PeterO

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    Both velocity and acceleration are vectors
     
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