Steam transforms into gas as it escapes into the atmosphere. Even if you manage to capture the steam as it ascends, it can revert to H2O when it cools down. Due to the evaporation process, the final volume of water will differ from the original amount.
In static equilibrium, all forces balance out. Therefore, to simplify, start by breaking down F1 into its horizontal and vertical components. Since no other forces act horizontally, F1's horizontal component is known to be 40N. This information can be used to determine the vertical component using the Pythagorean theorem. Once the components are established, simply add the vertical components to calculate the difference between the upward and downward forces.