Calculating Momentum of a Spacecraft with Thruster Firing?

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Homework Help Overview

The problem involves calculating the momentum of a spacecraft that is initially traveling at a certain velocity and experiences a force from a thruster firing in the opposite direction. The spacecraft's mass and the duration of the thruster firing are provided, along with the force exerted by the thruster.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the need to show work for assistance and question the initial attempts at solving the problem. There is a focus on the correct use of units and the application of the impulse-momentum theorem.

Discussion Status

Participants are actively engaging with the problem, identifying issues with unit conversions and the setup of the equations. Some guidance has been offered regarding the impulse-momentum relationship and the importance of checking signs in the equations.

Contextual Notes

There is an emphasis on the requirement to convert time from minutes to seconds, which is a critical aspect of the problem setup. The discussion reflects a need for clarity on the application of the impulse-momentum theorem.

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Homework Statement



a 1.0*10^4kg spacecraft is traveling through space with a speed of 1200 m/s realtive to earth. a thruster fires for 2.0 min, exerting a continuous force of 25kN on the spacecraft in a direction opposite the spacecraft s motion . calculate the initial momentum and the fianl momentum kof the spacecraft .



Homework Equations





The Attempt at a Solution

 
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You need to show work here in order to get help. Those are the rules. What have you tried so far? What are you thoughts on the problem?
 
(-25*10^3)(2.0)=(1.0x10^4)(1200)+(1.0*10^4)(mvi)
 
OK. Your big problem is with units. You have seconds on one side of the equation and minutes on the other side of the equation.

Also, remember the equation is:

Impulse =Change in Momentum.
J=\Delta p=p_f-p_i

Check your signs on the RHS of your equation.
 
Last edited:
ok so it would be 120s instead of 2.0min
 
(-25*10^3)(120)= (1.0*10^4)(mvi)-(1.0x10^4)(1200)
 
jamiescience said:
(-25*10^3)(120)= (1.0*10^4)(mvi)-(1.0x10^4)(1200)

That looks good to me.
 

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