Twelve horizontal telephone wires are supported by a vertex telegraph post , 5 wires ecrossing from the north and 7 wires from the rest . If all the wires are under the same tension , in which direction should the stay wire be fixed ? What is the resultant ten be fixed ? What is the resultant tension in the stay wire ?

Explanation

Let the tension in each wire be T N and the resultant tension be R N inclined at an angle `theta ` as
Total tension due north = 5 TN
Total tension due east = 7 T N
`tan theta = (5T)/(7T) = 0.71 `
`theta = 35.3^(@)` south -west
Resultant tension in the stay wire
`sqrt(5^(2)T^(2)+7^(2)T^(2))`
` = 8.6 T N `