If you have a board, say a standard 2x4 of finite length, where one end is fixed in a cement wall and the other end is free, and you begin adding weight to the free end until it breaks, where will the board break? Assume the board is made of typical wood and it is perpendicular to the wall in which it's affixed.
I was asked this question over 20 years ago in a job interview and I never knew if I answered correctly.
I answered that I thought the board would break in the middle. I figured the force bending the free end would be countered by an opposite force from the other end and they'd meet in the middle. I also noted that I'd never seen a tree branch break at the trunk. They always seem to break near the middle.