(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A space capsule was left rotating rapidly about its axis at N = 34.0 rev/min after a collision with another capsule.

You are the flight controller and have just moments to tell the crew how to stop this rotation before they become ill from the rotation and the situation becomes dangerous. You know that they have access to two small jets mounted tangentially at a distance R = 3.11 m from the axis, as indicated in the figure. These jets can each eject 13.7 g/s of gas with a nozzle speed of v = 712 m/s. Determine the length of time these jets must run to stop the rotation? In flight, the moment of inertia of the ship about its axis (assumed constant) is known to be 3872 kg·m2.

2. Relevant equations

rotational momentum of station = angular momentum of the jets

--> rotational momentum of station = (moment of intertia)*(angular velocity)

--> angular momentum of jets = (mass)(speed)(radius)

3. The attempt at a solution

--> therefore (momentum of inertia)*(angular velocity) = (mass)*(speed of gas ejected)*(distance from axis)

--> mass divided by the grams/second of gas = seconds needed

--> then divide that answer by 2 because there are 2 jets

(3872*3.56rad/s)/(.0137*3.11)=3.24x10^5 kg

3.24x10^5 /.0137=2.36x10^7 sec

divided by 2 jets=1.18x10^7 seconds

I used N for the angular velocity because I couldn't figure out a way to get it from the velocity given since I didn't know the mass yet. Maybe that is why I can't get it right? Thanks for any help!

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# Homework Help: Out of control space station

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