# Momentum problem.

1. Dec 19, 2007

### pebbles

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. Dec 19, 2007

### CaptainZappo

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.

3. Dec 19, 2007

### uber

Initial Momentum = Final Momentum.

Run with that and see if it gets you anywhere.

4. Dec 19, 2007

### pebbles

uh, i'm confused.
i don't know the final velocity of the rockets....

5. Dec 19, 2007

### pebbles

or wait, would the rockets' initial velocity be zero?

6. Dec 20, 2007

### CaptainZappo

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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