Physics - NLM Question with Solution | TestHub

A light string passing over the fixed smooth pulley $P_1$ carries the mass $m_1$ at one end and supports the axle of a light movable pulley $P_2$ at the other. A second light string passing under $P_2$ carries masses 100 gm and 300 gm at its two ends. All pulleys and strings are light and smooth. What should $m_1$ be so that the 100 gm mass remains at rest? (Take $g=10$ m/s²)