How can you determine the net force of a bottle who's contents are kept under 2 atm of pressure, and it has a 1 cm opening for example? a1v1=a2v2 doesn't seem to apply, and the flowrate=dav doesn't seem to either. I suspect it is bernoulli's equation, but I am unsure. I know P=F/A, but how do you find the pressure? is it simply the pressure difference?