What formula is used to determine sling tension?

The formula for determining sling tension is derived from the principles of mechanics concerning weight distribution and the angles formed by the slings during lifting operations. In this case, the correct formula relates the length of the sling, the weight being lifted, and the height at which the load is being lifted, taking into consideration the number of slings used.

When a load is lifted, the force exerted on the sling can be influenced by the load's weight and the angle at which the sling is positioned. The formula, which includes the sling length multiplied by the weight, and then divided by the sling height and the number of slings, helps to calculate how much tension each sling experiences. The reasoning behind this is that as you increase the height of the lift or the number of slings used, you effectively distribute the load more evenly, reducing the tension on individual slings.

In contrast, the other options do not maintain the correct relationships among sling length, weight, sling height, and the number of slings. They either misrepresent the units or the necessary calculations required to achieve an accurate tension assessment. Therefore, choice A correctly captures the principle behind calculating sling tension in rigging practices.