Why is it advisable to allow telephone wires to sag between poles?

Answer 1

because telephone wires might contract and may eventually snap during cold days. hence, it is advisable to allow them to sag during summer days to allow contraction for cold days.

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Answer 2

Telephone lines are longer in a warm summer and shorter in a cold winter. Hence, they sag more on hot summer days than in winter. If the lines are not strung with enough sag in summer, they might contract too much and snap during the winter, especially when carrying ice.

Conceptual Physical Science Hewitt/Suchocki/Hewitt

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Also, a wire suspended between two points must sag because it's physically impossible for the sag to be zero.

Imagine a horizontal string: an element in the middle has only horizontal forces acting on it, so there is nothing to support its weight. Therefore it's impossible.

Answer 3

So that electricity can pass through the wires quickly to get to their destination.

Gravity weighs down on the middle part of the wires more than on the sides because of the unsupported weight there.

Answer 4

When its winter the wires will contract (shrink) the extra wire will reduce the risks of tearing it.

Answer 5

Heat from the sun makes the wires expand, so they sag more during daylight or warm days. When the temperature cools at night, the wires contract again.