A block of mass m is placed on a surface with a vertical cross selection given by $\;y=\large\frac{x^{3}}{6}\;$ . If the coefficient of the friction is 0.5 , The maximum height above the ground at which the block can be placed without slipping is :

Question

$(a)\;\large\frac{1}{6}\;m \qquad(b)\;\large\frac{2}{3}\;m\qquad(c)\;\large\frac{1}{3}\;m\qquad(d)\;\large\frac{1}{2}\;m$