In a four-point lift with a load of 7750 LBS, sling length 6 ft and vertical distance 4 ft, calculate the sling stress per leg (nearest pound).

• A. 2700 LBS of sling stress per leg
• B. 2906 LBS of sling stress per leg
• C. 3100 LBS of sling stress per leg
• D. 3200 LBS of sling stress per leg

Answer: (B)

In a four-point lift, the load is shared among the four sling legs, and each sling carries a tension that has a vertical component supporting the weight. The vertical components from all four slings add up to the total load: 4 × T × cos(theta) = W. The angle theta between each sling and the vertical comes from the sling length and the vertical distance: cos(theta) = vertical distance / sling length = 4 ft / 6 ft = 2/3. Solve for the tension per leg: T = W / (4 cos theta) = 7750 / (4 × 2/3) = 7750 / (8/3) = 7750 × 3 / 8 = 2906.25. Rounding to the nearest pound gives 2906 pounds per leg.