Question

Two uniform rods of different materials $M_{1}$ and $M_{2}$ have lengths $2\, m$ and $3 \,m$, respectively. The mass per unit length of rods $M_{1}$ and $M_{2}$ are $1\ kg$ and $2\ kg$ respectively. If the rods are arranged, as shown, the position of the $cm$ relative to point $O$ is

• A. 4.9 m
• B. 3.9 m
• C. 2.9 m
• D. 2.2 m

Answer 1

Answer: (C)

2.9 m

Answer 2

The position of CM relative to point
$O=\frac{l_{1}+l_{2}}{\sqrt{3}}$
$=\frac{2+3}{\sqrt{3}}=\frac{5}{1.732}$
$=2.886\, m =2.90 \,m$