Answer to Question #71121 in Physics for Angelo Mathews

Question

No matter how tightly we pull the clothsline it always sags in the middle.Why?

Thank You

Answer 1

Tension is a force usually associated with a rope or a cable; it is a "response" force. In other words, if one pulls on a rope, the rope "fights back" by resisting being stretched. If the rope has negligible mass, the force exerted at one end is transmitted undiminished to each adjacent piece of rope along its entire length to the other end.
It is clear that no matter how much force is applied in horizontal direction, there always must be a vertical component of tension to counteract the weight. So, you may be the strongest person in the world, but you will still find it impossible to keep the rope (or clothes line) absolutely horizontal!