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Homework Help: Jet Planes

  1. Sep 8, 2010 #1
    1. The problem statement, all variables and given/known data

    A jet plane is cruising at 300 m/s when suddenly the pilot turns the engines up to full throttle. After traveling 2 km, the jet is moving with a speed of 400 m/s. What is the jet's acceleration (in m/s/s) during this interval assuming the acceleration to be constant?

    2. Relevant equations

    I was thinking that in order to go further you would have to solve for the seconds? So I used v=m/s and solved for s, which was then 5s. But I'm not sure where to go from there?

  2. jcsd
  3. Sep 8, 2010 #2


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    Initial and final velocities are given. Displacement is given. Find the kinematic equation which relates Vi, Vf, x and a. And solve for a.
  4. Sep 9, 2010 #3
    But the only kinematic formulas I find include time, which isn't given.
  5. Sep 9, 2010 #4
    Well, I tried vf=vi+a(t) but I got 20m/s/s, which was wrong.
  6. Sep 9, 2010 #5


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    v2f - v2i = 2as

    Substitute the values and find a. Here s = 2000 m.
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