JEE Main 2016 — Laws of Motion Question with Solution

A rocket is fired vertically from the earth with an acceleration of 2g, where g is the gravitational acceleration. On an inclined plane inside the rocket, making an angle $\mathrm{\theta }$ with the horizontal, a point object of mass m is kept. The minimum coefficient of friction ${\mathrm{\mu }}_{\mathrm{m}\mathrm{i}\mathrm{n}}$ between the mass and the inclined surface such that the mass does not move is: