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Homework Help: Exhaust Gas speed

  1. Oct 13, 2008 #1
    1. The problem statement, all variables and given/known data
    A 4200kg rocket is to be accelerated at 4.0g at take-off from the Earth.
    If the gases can be ejected at a rate of 28 kg/s, what must be their exhaust speed?
    2. Relevant equations

    Fthrust=mv2-mv1/t2-t1

    3. The attempt at a solution

    Multiplied 4200kgx4x9.8/28kg/s=-5900
     
  2. jcsd
  3. Oct 13, 2008 #2

    G01

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    Your work seems fine to me. Do you have any specific questions on this problem?
     
  4. Oct 13, 2008 #3
    The answer is wrong and don't understand why it is?
     
  5. Oct 13, 2008 #4
    I figured it out for future reference, since the rocket has to overcome 1g you add it to the 4g. You use the same equation. 4200x5x9.8/28=7400m/s
     
  6. Oct 13, 2008 #5

    G01

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    Good catch! Nice job.:smile:
     
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