16758. In a screw jack, the effort required to lift the load is given by(where W = Load lifted, α = Helix angle, and φ = Angle of friction.) September 13, 2025 by Admin P = W tan (α – φ) P = W tan (α + φ) P = W tan (φ – α) P = W cos (α + φ) ✅ The correct answer is option B.