1. The problem statement, all variables and given/known data A barrel with diameter 80cm is completely full of water and sealed except for a piece of tube extending vertically through the lid with a diameter of 0.8cm. It's asking what height would you have to fill the small tube with in order to make the lid of the barrel pop off. The upward force required to do this is 450N. 2. Relevant equations Pressure=Force/Area Boyant F= density (fluid) x A x h x gravity=density (fluid) x gravity x height 3. The attempt at a solution I tried finding the areas of both the barrel and the tube, but I may be getting confused with the units. I got: A(barrel)=10053.09; A(tube)=4.021 by using 2Pi x r^2, and from the P=F/A formula, i got the pressures to be: P(barrel)=.01119 and P(tube)=111.9. From here I'm kind of lost. I tried to plug these numbers into the density x g x h equation, but they came out wrong. Any help as to where I should go from here (or how to start it if it's that bad) would be much appreciated.