Calculating the Speed of Exhaust Gas for a Rocket in Deep Space

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Homework Help Overview

The problem involves calculating the speed of exhaust gas from a rocket in deep space, where gravitational effects are negligible. The scenario includes the rocket ejecting a portion of its mass and experiencing a specific acceleration.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to apply conservation of momentum but struggles with the presence of the rocket's velocity in the equation. Some participants question the use of the force equation and its relevance to the problem, while others seek clarification on the mass variable involved in the momentum change.

Discussion Status

The discussion is active, with participants exploring different approaches to the problem. Some guidance has been offered regarding the application of momentum and force equations, although there is no clear consensus on the best method to proceed.

Contextual Notes

Participants note the lack of specific values for the rocket's velocity, which complicates the ability to express the exhaust gas speed numerically. The problem is framed within the constraints of a homework assignment, which may limit the information available for discussion.

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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 can't 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! :)
 
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What's wrong with F = m*a = Δmv/Δt ?
 
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:
 
ooohh! I got it now! Thanks for the help! :)
 

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