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Homework Help: Mechanics problem

  1. Mar 6, 2010 #1
    1. The problem statement, all variables and given/known data
    Car A, which is travelling at a constant velocity of 15 ms-1, passes Car B, which is stationary, at time t = 0. At the instant that it is being passed, Car B begins to move, accelerating at a constant rate of 0.1 ms-2 in the direction in which Car A is travelling. At what speed will Car B be travelling as it passes Car A (in ms-1)?

    2. Relevant equations



    3. The attempt at a solution
    Ok so I know that this is a relative velocity question? so the relative velocity will decrease by 0.1 per second. But I then get stuck, im having trouble understanding the situation I think]

    cheers
     
  2. jcsd
  3. Mar 7, 2010 #2
    Do you know the Kinematics Equations?

    http://wiki.answers.com/Q/What_are_the_kinematic_equations

    You need to find the right equation which will find the speed of the car in question as a function of time. Then you find the point where the displacement of both cars is equal, and calculate for the speed.

    Alternatively, you could draw a graph and plot the displacement of the cars against time. That way, the speed of the car will be dx/dt at the point that they cross.
    Hope that helps
     
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