Question 65 of 130
A circular disc of radius is removed from a bigger circular disc of radius such that the circumferences of the discs coincide. The centre of mass of the new disc is from the centre of the bigger disc. The value of is
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Answer: (A)
In this question distance of centre of mass of new disc is not .
$\begin{aligned}
& -\frac{3 \mathrm{M}}{4} \alpha \mathrm{R}+\frac{\mathrm{M}}{4} \mathrm{R}=0 \\
& \Rightarrow \alpha=\frac{1}{3}
\end{aligned}$
$\begin{aligned}
& -\frac{3 \mathrm{M}}{4} \alpha \mathrm{R}+\frac{\mathrm{M}}{4} \mathrm{R}=0 \\
& \Rightarrow \alpha=\frac{1}{3}
\end{aligned}$
