Level 4 Cube Field A Level Mathematics > Moments> Help Required?

A level mathematics > moments> help required? - level 4 cube field

A horizontal force of increasing size to half of the face of a cube with 50 cm in the perpendicular applied to the face. the coefficient of friction between the cube and the surface is a 0.4 and the cube on a flat surface. What happens to the cube?

In assuming that the films? But I'm not sure? Can someone show the work in the name of the show "why he slips"

Thank you very much people appreciate the help!