The stretching force in a clothesline carrying a load of wash is appreciably greater when the clothesline...?

Question

The stretching force in a clothesline carrying a load of wash is appreciably greater when the clothesline is strung horizontally than when it is strung vertically. Why?

When you answer the question, please also explain WHY, because I don’t just want the answer, I also want to learn thanks! =)

Answer 1

Because the force exerted on the line is proportional to the reciprocal of the sine of the angle (with respect to the line) that the force is applied along (draw a force vector diagram). That's the reason that power lines are never pulled out horizontal. They always have a small amount of 'sag' to them.

Doug