Question

Two particles of mass $5\,kg$ and $10\,kg$ respectively are attached to the two ends of a rigid rod of length 1m with negligible mass. The centre of mass of the system from the $5\,kg$ particle is nearly at a distance of :

• A. 33 cm
• B. 50 cm
• C. 67 cm
• D. 80 cm

Answer 1

Answer: (C)

67 cm

Answer 2

Let position of centre of mass be ${(x_{c.m}, 0)}$
$x_{cm}=\frac{m_{1}x_{1}+m_{2}x_{2}}{m_{1}+m_{2}}$
$=\frac{5 \times 0+100 \times 10}{5+10}$
$=\frac{200}{2}$
$=66.66\,cm$
$x_{cm}=67\,cm$