Question

A system consisting of two masses connected by a mass less rod lie along the $x-$axis. A $0.4kg$ mass is at a distance $x=2m$ while a $0.6kg$ mass is at a distance $x=7m$. The $x-$coordinate of the centre of mass is

• A. $5m$
• B. $3.5m$
• C. $4.5m$
• D. $4m$

Answer 1

The correct option is A $5m$

$x_{CM}=\frac{m_1{x}_1+m_2{x}_2}{m_1+m_2}$

$x_{CM}=\frac{0.4\times 2+0.6\times 7}{0.4+0.6}=5$