Angle of Repose

                                       Angle of Repose

Edge (ANGLE) of Repose - Where the edge of tendency (α) of the plane is equivalent to the point of contact (ϕ). 

It is the edge of tendency (α) of the plane to the flat, at which the body just starts to descend the plane. A little thought will demonstrate that the body will start to descend the plane if the edge of tendency (α) of the plane is equivalent to the point of erosion (ϕ). From Fig. 1.18, we find that 

Edge  (ANGLE) of Repose