In the figure given, the system is in equilibrium. What is the maximum value that W can have if the friction force on the 40 N block cannot exceed 12.0 N

The free-body diagram of the block is as shown in adjacent figure. ∵f0max =12.0N( Given )∵T1max =12.0NThe free-body diagram of knot is as shown in adjacent figure. T2sin⁡30∘=W … (i) T2cos⁡ 30∘=T1 … (ii)  Divide (i) by (ii), we get, tan⁡30∘=WT1 or W=T1tan⁡30∘=0.577T1∴Wmax=0.577T1max=0.577×12.0N=6.92N.