A particle of weight \[W\]rests on a rough inclined plane which makes an angle \[\alpha \] with the horizontal. If the coefficient of static friction \[\mu =2\] tan a, find the horizontal force \[H\] acting transverse to the slope of the plane when the particle is about to slip.

• A. \[2W\,\sin \alpha \]        
• B. \[W\,\sin \,\alpha \]
• C. \[\frac{\sqrt{3}}{2}W\,\sin \,\alpha \]     
• D. \[W\sqrt{3}\,\sin \,\alpha \]