Problem

A horizontal force

F = \frac{mg}{3}

is applied on the upper surface of a uniform cube of mass

m

and side

a

which is resting on a rough horizontal surface having

\mu = \frac{1}{2}

. The distance between lines of action of

mg

and normal reaction is a.

\frac{a}{2}

\frac{a}{3}

\frac{a}{4}

d. None of these