When the angle between sling legs and the vertical grows, the tension in each sling does what?

• A. Decreases
• B. Increases
• C. Stays the same
• D. Varies with angle

Answer: (B)

As the angle from vertical increases, each sling leg must supply more of the load's vertical support, so the tension in each leg rises. Picture the two legs pulling upward along their lengths; the vertical component of each leg’s tension is T cos θ, and these must add up to the total weight W. So 2 T cos θ = W, which gives T = W / (2 cos θ). When θ grows, cos θ shrinks, making T larger. This is why widening the sling spread increases the tension in each leg. For example, with a 2000 N load, T is 1000 N when the legs are vertical, but rises to about 1155 N at 30°, 2000 N at 60°, and climbs dramatically as the angle approaches horizontal. Practically, keeping the legs closer to vertical keeps tension manageable and safer.