Answer to Question #96277 in Classical Mechanics for John

Question

a pole support bby steel wire is in the way of construction site.in order to move heavy machines the steel wire must be moved 4m closer to the pole if the pole height is 30m and cable is currently fastened to the ground 12m from the pole how much steel wire need to cut off from the cable when they move it

Answer 1

Initial length of wire:

$$l_0=\sqrt{30^2+12^2}=32.311\ m$$

Finial length of wire:

$$l=\sqrt{30^2+(12-4)^2}=31.048\ m$$

$$\Delta l=32.311-31.048=1.263\ m$$