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Homework Help: Kinematics problem

  1. Sep 25, 2005 #1
    Hello, thanks for reading =)

    Let's just jump into it...
    At the instant the light turns green, a car accelerates from rest at a rate of 1.8m/s^2. A truck gets to the intersection by the time the light changes [and therefore doesn't have to stop]. The truck is travelling at a constant velocity of 8.5m/s.

    What will be the displacement of the car [assuming the intersection is 0] when it passes the truck, and at what time will this occur?


    I've been trying to solve it by using a displacement-time graph, but obviously the car will have a curved graph, and I can't figure out the equation of it's line. Any tips on how to go about this, as well as tips to solve the question would be great.

  2. jcsd
  3. Sep 25, 2005 #2
    you will find this formula useful:
    [tex]d = v_i t + 1/2at^2[/tex]
  4. Sep 25, 2005 #3
    Aha! Just what I was looking for, and thanks for not giving me the answer outright, it made it much more rewarding to get the right answer.

    Thanks again!
  5. Sep 25, 2005 #4
    Did you get the right answer? And I'm glad you appreciate when people don't just give away the solution. :)
  6. Sep 26, 2005 #5
    Yep, got it. That was all I needed for it to click in my brain.
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