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Homework Help: Constant Acceleration

  1. Nov 13, 2009 #1
    1. The problem statement, all variables and given/known data
    A jumbo jet needs to reach a speed of 300 km/hr on a runway for take off. Assuming a constant acceleration and a runway 2 km long, what minimum acceleration from rest is required to get the jet in the air?

    2. Relevant equations
    I tried using the equation:

    But there is also:

    3. The attempt at a solution
    I set up the following variable list:
    Xo=1.5 Vo=?
    X=21.5 V=0
    t=? a=-9.8

    I plugged these values into the equations mentioned above to get a final answer of 2250km/hr^2 for the acceleration needed. Would this be correct?
  2. jcsd
  3. Nov 13, 2009 #2

    Doc Al

    User Avatar

    Staff: Mentor

    This should be:
    V^2 = Vo^2 + 2a(X-Xo)

    Almost; I think you made an arithmetic error with the decimal point.

    (I merged this thread by mistake--then unmerged it. So I might have changed its title. My apologies.)
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