Block B lying on a table weighs w. The coefficient of static friction between the block and the table is μ. Assume that the cord between B and the knot is horizontal. The maximum weight of the block A for which the system will be stationary is

Let weight of A is w'. From the free body diagram, for equilibrium of the system,T cosθ = μN = μw        ..........(i)T sinθ = w'        ..........(ii)where, T = tension in the thread lying between knot and the support.On dividing Eq. (ii) by Eq. (i), we getTsinθTcosθ=w'μw⇒tanθ=w'μw⇒  w'=μwtanθ