1. The problem statement, all variables and given/known data Hi, this is not really an academic homework but it is something I'm trying to solve for my future project. I have a background in electrical engineering hence I'm having a hard time solving the forces problem. https://dl.dropboxusercontent.com/u/43124243/Force_problem.png [Broken] I'm trying to calculate the force in N over the range of operational angles (15-40°) required to lift the platform and steps. I want to print a chart in Excel, so I'm trying to find the formula for calculating the required force. The mass of steps (FN1) - 700 kg The length of steps (A→B) - 2000 mm The mass of platform (FN2) - 300 kg The length of platform (B→C) - 500 mm The fixed position of linear actuator (D) - 3900 mm from steps' pivot point Operational angles (α) - 15-40° 2. Relevant equations I assume that this equation is relevant F = m × g × cos (θ) 3. The attempt at a solution Here is my poor attempt at the solution: e.g. @ angle 40° F = (½ × msteps + mplatform) × g × cos(α) F = (½ × 700 + 300) × 9.8 × cos(40°) F = 4.88 kN I suspect that this part is correct although I do not know how to add the linear actuator's tilt angle (β) into the equation. I can find the angle β itself via SOHCAHTOA rule but I'm not sure what to do with it next. Any help will be much appreciated.