# How much additional altitude can rocket obtain with launch assist.

1. Oct 19, 2011

### Futabo

1. The problem statement, all variables and given/known data
We have 2 model rockets identical in all ways (weight, height, mass, propellant, etc). The first rocket is launched like most rockets (0 ft/sec) and reaches 1000ft. For the second rocket we use a SUPER rubberband launch system. The launch system sends the rocket to say, 150 ft/sec before the rocket ignites. What altitude will the 2nd rocket reach? Please see the attached image.

2. Relevant equations
I assume part of it involves Kinematic Equations. Something like V² = U² +2*a*s. After that do we just add together 1000+the result? Or is it far more complex? I heard that rockets perform better at speed. In theory, are the gains in altitude significant? The plan is to do a real world test! My profession is in advertising and have loved rockets since childhood, but physics is way over my head!

3. The attempt at a solution
1000 + 1147 = 2147
BAM! How's that?

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2. Oct 20, 2011

### PeterO

A rocket burns fro a specific time - applying a calculatable impulse and thus increase in momentum. One the fuel runs out the rocket will be traveling at high speed, so continues [slowing down] until it stops rising, and returns to Earth.

I would draw Velocity time graphs of the two flights - it becomes [should anyway] clear from there.