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Lost on equations

  1. Jan 24, 2010 #1
    1. The problem statement, all variables and given/known data

    A student is running at her top speed of 4.7 to catch a bus, which is stopped at the bus stop. When the student is still a distance 38.2 from the bus, it starts to pull away, moving with a constant acceleration of 0.180 .


    2. Relevant equations
    This is where I am stuck on I just need the relative equations and I will be able to give this a shot.


    3. The attempt at a solution

    What I know is that I will have to end up making two equations. One for the bus and one for the student then make the equal to each other.
     
  2. jcsd
  3. Jan 24, 2010 #2
    You need to make two equations for distance and set them equal to each other. One equation should be the distance from the student's starting spot, and the other should be the distance the student has traveled.
    d = X(i) + 1/2 a t^2
    d = v * t
    v * t = x(i) + 1/2 a t^2
    1/2 a t^2 - v * t + x(i) = 0
     
  4. Jan 24, 2010 #3
    what are trying to find out?
     
  5. Jan 24, 2010 #4
    Oh right I guess I forgot what I am trying to find. I need to find out when the student reaches the bus, how much has she ran, velocity of the bus when she catches it, min speed for her to catch it, what if her velocity was shorter and find all of the other things again.
     
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