Question

Two persons A and B having masses 50 kg and 60 kg respectively are sitting at the two extreme to a 4 m long platform of mass 40 kg kept on smooth ice. If they come to the middle of boat then how far does the boat on the ice during the process.

Answer 1

$x_{cm}=\frac{m_1{x}_1+m_2{x}_2}{m_1+m_2}=\frac{50\times (-2)+60\times 2+40\times 0}{50+60+40}=\frac{2}{15}=0.133m=13.33cm$

if the center vof mass doesnt moved then boat must moved $\frac{2}{15}m$ towards 60kg person