- #1
djdoug99
- 15
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I'm trying to calculate the acceleration of a high altitude balloon at different altitudes. In excel I've got the temperature, air pressure, and air density for a given altitude (thanks to NASA). Right now I am calculating the net force on the balloon with:
Fnet= Fb-Fm
Fb = Buoyant force = density of air*volume*9.81
Fm= (mass of balloon+mass of payload+(volume*density of helium))*9.81
For whatever volume I put in for the balloon I only get a positive net force until about 55,000 feet. I'm thinking it is because I am not taking into account the increase of air that will be displaced by the balloon as it gets higher and higher, but I am not sure how to model that mathematically. Any insight as to how to do this would be appreciated.
Fnet= Fb-Fm
Fb = Buoyant force = density of air*volume*9.81
Fm= (mass of balloon+mass of payload+(volume*density of helium))*9.81
For whatever volume I put in for the balloon I only get a positive net force until about 55,000 feet. I'm thinking it is because I am not taking into account the increase of air that will be displaced by the balloon as it gets higher and higher, but I am not sure how to model that mathematically. Any insight as to how to do this would be appreciated.
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