11401. In a screw jack, the effort required to lift the load W is given by (where α = Helix angle, and φ = Angle of friction) September 8, 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.