In a two-sling lift, at what angle does the load on each sling become equal to the weight of the load?

In a two-sling lift, at what angle does the load on each sling become equal to the weight of the load?

• A. 25 Degrees
• B. 30 Degrees
• C. 35 Degrees
• D. 40 Degrees

Answer: (B)

In a two-sling lift, the load is shared between the two slings, with each sling providing a vertical component of its tension that supports the weight. If we measure the angle from the horizontal, each sling’s vertical component is T sin φ, where T is the tension in that sling and φ is the angle with the horizontal. The two slings together must support the full weight, so 2 T sin φ = W. The load carried by each sling equals the tension T. To have the load on each sling equal the total weight, set T = W and solve: 2 W sin φ = W, which gives sin φ = 1/2, so φ = 30 degrees. Therefore, when each sling makes 30 degrees with the horizontal, the tension in each sling equals the weight of the load. (If you were using angle from vertical, the equivalent would be 60 degrees.)

In a two-sling lift, the load is shared between the two slings, with each sling providing a vertical component of its tension that supports the weight. If we measure the angle from the horizontal, each sling’s vertical component is T sin φ, where T is the tension in that sling and φ is the angle with the horizontal. The two slings together must support the full weight, so 2 T sin φ = W. The load carried by each sling equals the tension T. To have the load on each sling equal the total weight, set T = W and solve: 2 W sin φ = W, which gives sin φ = 1/2, so φ = 30 degrees. Therefore, when each sling makes 30 degrees with the horizontal, the tension in each sling equals the weight of the load. (If you were using angle from vertical, the equivalent would be 60 degrees.)