Physics - NLM Question with Solution | TestHub

Take the wedge, the pulleys, the block $m$ and the string together. The string tension $T=F$ acts on the pulleys of the wedge in two parts: at the lower pulley the string pulls with $T$ toward the block (left) and $T$ up along the incline; at the upper pulley with $T$ down along the incline and $T=F$ horizontally to the right.

Net horizontal force on the wedge: $-T+T\cos \theta -T\cos \theta +T=0$. There is no friction, so the acceleration of the wedge is zero.