A right-angled triangular block of mass M rests on a horizontal table . The inclination of the block is `30^(@)` with the table . A cubical block of mass m is placed on the incline of the block . What horizontal force must be applied on M so that m may remain stationery relative to the block ?
[Hint: Apply d' Alember's principal and consider free-body diagrams of m and the system ( m+ M).]

Answer

( M + m) `g//sqrt3`