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Momentum problem.

  1. Dec 19, 2007 #1
    1. The problem statement, all variables and given/known data
    A space probe with mass of 7.60 * 10^3 kg is traveling at 125 m/s. Missions control decides that a course correction of 30 degrees is needed. and instructs probe to fire rockets perpendicular to present direction of motion. If gas expelled by rockets has speed of 3.200 km/s, what mass of gas should be released?

    2. Relevant equations

    3. The attempt at a solution
    3.200 km/s-->3200 m/s

    I'm totally stuck on this one. I'm not good at physics, so I need someone to walk me through this problem thoroughly.

    Thanks in advance.
  2. jcsd
  3. Dec 19, 2007 #2
    Use conservation of momentum considerations.

    I can't help you too much because you've shown no attempt at solving this problem on your own.
  4. Dec 19, 2007 #3
    Initial Momentum = Final Momentum.

    Run with that and see if it gets you anywhere.
  5. Dec 19, 2007 #4
    uh, i'm confused.
    i don't know the final velocity of the rockets....
  6. Dec 19, 2007 #5
    or wait, would the rockets' initial velocity be zero?
  7. Dec 20, 2007 #6
    The initial velocity of the gas would be zero with respect to the probe. Consider the total momentum of the proble + gas system. It is this vector quantity that remains unchanged.
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