Helium balloons are a very common sight at carnivals, birthday parties, etc. but how fast do they accelerate when a child accidentally lets go?
Bouyancy force=(density of fluid)(V of fluid displaced)(gravity)
Mass of gas in the balloon
101325Pa*(4.00L(1m/10dm)^3)=n*8.314J/molK*(20 degrees C+273K)
0.166mol*4.0026g/mol*1kg/1000g=0.000664Kg He gas
Force due to gravity
Acceleration of balloon ignoring drag force
The drag force increases as the velocity of the balloon increases and at some point keeps the balloon from accelerating further and the balloon will travel upwards at a constant velocity.