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Homework Help: F=ma help

  1. Dec 2, 2009 #1
    1. The problem statement, all variables and given/known data

    what force is required to give a projectile weighing -475 N an acceleration of 3.00x10^3m/s^2

    2. Relevant equations


    3. The attempt at a solution

    -175 N=m (-9.81m/s^2)
    m=48.4 Kg

    f=145000 N

    hi thanks so much for your help, I'm just wondering if I have completed this correct. I'm am just confused because it says that the projectile weighs -475 N so I have to change that into it's mass then into it's force.

    thank you. have a good night.
  2. jcsd
  3. Dec 2, 2009 #2
    Seems like it's right.
  4. Dec 2, 2009 #3
    This is correct if the applied force F is horizontal. If the applied force F is vertical (upward, against weight), then

    [tex]\sum[/tex]F = F - mg = ma
    F = m(a + g)
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