Three concrete poles with the same size diameter=1.2 m, the same mass= 2000kg, density, and structure are piled horizontally on each other and on the top of a rough surface, coefficient of friction between surface and concrete pole= 0.5. To help you get the picture, two of these poles are at the bottom and the third one is on the top of them, in the middle. Calculate the minimum angle which the direction of the force acting between the cylinders and the rough surface makes with the vertical?
The blocks are arranged like a triangle from the side (all cylinders are identical):