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Drag Force and Terminal Speed

  1. Oct 28, 2009 #1
    1. The problem statement, all variables and given/known data
    Missile Calculate the drag force on a missile 48 cm in diameter cruising with a speed of 270 m/s at low altitude, where the density of air is 1.2 kg/m3. Assume C = 0.75.

    2. Relevant equations

    Fd = -1/2p(v^2)CA

    3. The attempt at a solution

    -1/2(1.2)(270^2)(0.75(0.48) = -15746.4 what am i doing wrong?
  2. jcsd
  3. Oct 28, 2009 #2
    0.48 is the diameter, not the cross-sectional area of the missile.
  4. Oct 28, 2009 #3
    how do i calculate cross-sectional area?
  5. Oct 28, 2009 #4
    Well, the usage of the term 'diameter' and general impression of the appearance of the missile should clearly hint towards approximating it as a cylinder / having a round cross-section at least.
  6. Oct 28, 2009 #5


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    Homework Helper

    The question mentions diameter, so you're supposed to assume the missile is a cylinder.
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