An aircraft hangar is semi-cylindrical, with diameter 40m and length 50 m. A helicopter places an inelastic rope across the top of the hangar and one end is pinned to a corner, a A. The rope is then pulled tight and pinned at the opposite corner, B. Determine the lenghth of the rope.
So, first I find the diagonal line from A straight to B.
c^2=50^2+40^2
The answer is 64.03124……
Then, I find out that there is a semi-circle shape. So I find the length of the arc.
r=32.05162…….
Length=2*Pi*32.05162…..
=201.16008m……
But the correct answer is 80.30m
Can anyone tell me where i did wrong?
Best Answer
Hint: imagine the semicylindrical surface of the hangar as planar and apply Pytagora's theorem. If you flatten it to get a rectangle, the curve that you search becomes the diagonal of that rectangle.