A uniform cube of side a and mass `m` rests on a rough horizontal table. A horizontal force `F` is applied normal to one of the faces at a point directly above the centre of the face, at a height `(3a)/(4)` above the base. What is the minimum value of `F` for which the cube begins to tip about an edge?

Options

A. `mg`
B. `2/3mg`
C. `3/2mg`
D. `3/4mg`

Answer

B

Explanation

See the figure for tilting about `A` clockwise torque (due to `F`) should be greater than the anticlockwise torque about `A`.

`mgxxa/2=(F3a)/3, g=(2mg)/3`