A Rocket in Deep Space

  • Thread starter ch010308
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  • #1
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Homework Statement



A rocket is fired in deep space, where gravity is negligible. In the first second it ejects 1/160 of its mass as exhaust gas and has an acceleration of 15.9 m/s2.

What is the speed vgas of the exhaust gas relative to the rocket?
Express your answer numerically in kilometers per second.

Homework Equations



conservation of momentum: (m1v1 + m2v2)final = (m1v1 + m2v2)initial

The Attempt at a Solution



(159/160)M(vrocket + 15.9) - (1/160)Mvgas = Mvrocket

I go on to simplify it but I cant express vgas in numerical terms, as vrocket still remains in the equation. There is no value given for this so how can I solve the question?

Pls help! Thanks! :)
 

Answers and Replies

  • #2
LowlyPion
Homework Helper
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What's wrong with F = m*a = Δmv/Δt ?
 
  • #3
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hmmm... Are you saying that i should use m*a = Δmv/Δt for the change in momentum of the rocket? then wat will be the value of m? :confused:
 
  • #4
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ooohh!!! I got it now! Thanks for the help! :)
 

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