Two hemispheres of radii `R` and `r(lt R)` are fixed on a horizontal table touching each other (see figure). A uniform rod rests on to spheres as shown. The coefficient of friction between the rod and two spherers is `mu`. Then the maximum value of the ratio `(r)/(R)` for which the rod will not slide is :

Answer

`((r)/(R))_("min") = (sqrt(1 + mu^(2)) - mu)/(sqrt(1 + mu^(2)) - mu)`