question_answer 69)

                  Block A of weight 100 N rests on a frictionless inclined plane of slope angle \[{{30}^{o}}\] (Fig.). A flexible cord attached to A passes over a frictonless pulley and is connected to block B of weight W. Find the weight W for which the system is in equilibrium.

Answer:

                  Block A will be at rest if \[F=mg\sin 30{}^\circ \]                 \[=100\,\times \,\frac{1}{2}\,=50\,N\]