Question

A uniform metal disc of radius R is taken and out of it a disc of diametere R is out off from the end . The centre of mass of the remaining part will be

• A. $\frac{R}{4}$ from the centre
• B. $\frac{R}{3}$ from the centre
• C. $\frac{R}{5}$ from the centre
• D. $\frac{R}{6}$ from the centre

Answer 1

Answer: (D)

$\frac{R}{6}$ from the centre

$\begin{array}{c}{x}_{com}=\frac{M\left(0\right)+\left(\frac{-M}{4}\times \frac{R}{2}\right)}{M-\frac{M}{4}}\\ =\frac{-MR}{8\times \frac{3M}{4}}\\ =\frac{-R}{6}\end{array}$

Hence,

Option $D$ is correct answer.