1. The problem statement, all variables and given/known data Attached below 2. Relevant equations 3. The attempt at a solution My first confusion is with the pressure measuring device, i just converted the units into Pa by dividing by 1.02x10-5 such that: Pressure at the top of the tank = (0.07/1.02e-5) - (9800*0.3) = 3922.75Pa So on the cone the average pressure is (3922.75 + 0.05*9800) = 4412.75Pa The surface on which this force acts is the top part of the cone, where r = h*tan(30) , r = 0.0577, which means the surface is 0.031m^2 The force acts Vertically and horizontally but the horizontal components cancel each other out (right?) So the vertical force is: 4412.75*0.031*cos(60) = 68.4N, which isn't the correct result. This is the same method i was using to solve problems related to tilted rectangular plates, however now it is a conical surface should i be solving it differently ? Any help would be much appreciated, thank you!