Originally Posted by
OneEye
Each ceiling bolt will be subjected to T, the tension in the cord. Assuming 30 degree hang angle that T is W, the weight of the occupant. In your example, 200 lbs. The wall bolts happen to be subjected to a force of T, but it is based on the free body diagram of the wall bolt. Sum the forces of the lines coming into the bolt, and the bolt must handle any unbalanced forces to remain at rest. There are two forces acting on the bolt, one from the line to the ceiling, and one from the line to the hammock. The force in each is T or W (200 lbs). One is directed straight up, so Fy=+200lbs. One is directed towards the hammock, so Fy=-100lbs and Fx=+173lbs. Summing the forces we have Fy= +200-100 = +100 lbs. Fx = +173 lbs. The bolt must oppose these net forces, so 100 lbs down and 173 lbs towards the wall. Vector sum of these forces is sqrt(100^2+173^2) = 200 lbs.
The net result being W is a coincidence of the angles chosen...
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