Which of the following sling angles is considered the weakest?

When evaluating sling angles in lifting operations, the angle of the sling significantly impacts the load distribution and the stress on both the sling and the lifting equipment. A sling angle of 30 degrees is considered the weakest because it results in the highest tension in the sling.

At shallower angles, such as 30 degrees, the weight of the load is effectively distributed in a way that subjects the sling to greater forces. In contrast, as the angle increases toward 90 degrees, the tension in the sling decreases because the load is being lifted more directly upward, thereby reducing the resultant force acting on the sling.

Thus, a 30-degree angle increases the risk of sling failure due to the higher forces at play compared to the other angles presented. This greater tension can potentially exceed the sling's rated capacity, making it a critical angle to avoid in lifting operations. Proper rigging practices generally recommend maintaining sling angles above 30 degrees when possible to enhance safety and reduce the risk of accidents.