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Homework Help: Net Force of a Rocket and Acceleration

  1. Oct 18, 2007 #1
    1. The problem statement, all variables and given/known data
    An 8.0Kg rocket is fired and encounters a force of air resistance of 4.9N. If the rocket's engines applied 100N of thrust:
    A. What is the Net Force on the rocket?
    B. What is the Rocket's Acceleration?

    2. Relevant equations
    (A) F=MA
    (B) Is it (Vfinal - Vinitial)/T?

    3. The attempt at a solution
    F=(8.0KG)(A) = (8.0 x A) The paper tells me its 16.7N
    (B) I don't know if this is the right equation... but it must be about 2.9 M/S2 to get A above.
  2. jcsd
  3. Oct 18, 2007 #2


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    Homework Helper

    a) The rocket is fired vertically... just added up all the forces in the vertical direction... remember to take signs into account... you have 3 forces... thrust, gravity and air resistance.

    b) here use fnet = ma where fnet is what you get in part a).
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