Final answer:
The tension in the four vertical ropes from which Nellie hangs adds up to equal her weight. Each rope bears an equal share, which is a quarter of her total weight, ensuring she remains in static equilibrium.
Step-by-step explanation:
When Nellie hangs from a horizontal bar that is supported by four vertical ropes, the tension in these ropes work together to support her weight. Considering the forces involved, we can deduce that the direction of the tension in each rope is upwards counteracting the force of gravity.
If we think of a free-body diagram where tension forces are represented by arrows pointing upwards and gravity downwards for the system to be in static equilibrium, the sum of the tensions must equal the weight of Nellie. However with four ropes the tension in each rope does not need to be as large as the total weight. When the weight is evenly distributed, each rope will support an equal share. Therefore, if we combine the tension from all four ropes, it would equal Nellie's weight, making each rope's tension a quarter of her weight. Consequently, the correct answer to the question is A) add to equal her weight.